Smith & Wesson Forum

Go Back   Smith & Wesson Forum > >


Reply
 
Thread Tools Display Modes
  #1  
Old 09-29-2018, 12:02 AM
Eddietruett Eddietruett is online now
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2016
Location: South Carolina
Posts: 683
Likes: 329
Liked 1,165 Times in 364 Posts
Default Consistant Velocity vs Accuracy Question

Been loading many years and I know in theory that the more consistent the velocity, the better the accuracy. I ran into a weird situation today and maybe I'm over thinking or if not maybe someone can share some wisdom. I've been working with 3 different .357 mag bullets getting ready for deer and will use on coyotes as well. Using 158gr Hornady XTP, Sierra JHC and Speer JHP. Using the same load of 16.5gr of H110 the Speer is the most accurate out of my 8 3/8" Mod 686 with the XTP and Sierra not too far behind. Today I decided to chronograph the loads just to see the velocity I was getting. Shot 10 rounds through my Caldwell (which I'm aware is a lower end model) from 15 feet. The Sierra and XTP both averaged around 1375fps. The Speer averaged 1300fps. The difference of the Sierra and XTP was around 40fps. Not sure if that's about normal or not, but the surprise was the difference in high to low with the Speer was around 100fps but the Speer will shoot much tighter groups especially at 75 yards. I loaded all 3 at the same time on the same press and there were no die settings changed between bullets with the exception the seating plug was turned maybe 1/2 turn from bullet to bullet. When I noticed the difference, I shot another 10 shot group with the Speer and this time recorded the impact of each shot along with the velocity. I got the same variation in velocity but when a bullet varied 50-60fps over or under the average, I could see no noticeable difference in poi. I am shooting off a rest with a Red Dot Tube and granted my shooting skill makes this a very unscientific test. Is 50fps over or under the average just not enough to vary the accuracy? I found it strange that the load with the largest variance in velocity is the most accurate. And I can't figure out why one bullet has so much variance compared to the other 2. When I got home, I did check the diameters of all and they are all dead on .357" and checked about 25-30 random Speer bullets expecting to see a slight difference in diameter but everyone I checked was dead on the money. Am I just over thinking this?
Reply With Quote
  #2  
Old 09-29-2018, 12:24 AM
Rock185's Avatar
Rock185 Rock185 is online now
US Veteran
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Apr 2005
Location: Under the Tonto Rim
Posts: 920
Likes: 7,202
Liked 1,056 Times in 410 Posts
Question

I have always tried for consistent, low SD, small velocity spread, handloads. But apparently, others have made a serious study of this, and tight velocity spreads don't have much, if any, correlation with handgun and ammunition accuracy. Even shooting accurate handguns from a rest, I am not good enough to confirm this. Wish I knew more, or could point you toward authoritative sources, but that's all I can recall on the issue.
__________________
NRA Life, COTEP 640
Reply With Quote
The Following 2 Users Like Post:
  #3  
Old 09-29-2018, 01:12 AM
one eye joe's Avatar
one eye joe one eye joe is online now
US Veteran
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2008
Location: New England
Posts: 3,927
Likes: 3,215
Liked 3,322 Times in 1,420 Posts
Default

Quote:
Originally Posted by Eddietruett View Post
Been loading many years and I know in theory that the more consistent the velocity, the better the accuracy. I ran into a weird situation today and maybe I'm over thinking or if not maybe someone can share some wisdom. I've been working with 3 different .357 mag bullets getting ready for deer and will use on coyotes as well. Using 158gr Hornady XTP, Sierra JHC and Speer JHP. Using the same load of 16.5gr of H110 the Speer is the most accurate out of my 8 3/8" Mod 686 with the XTP and Sierra not too far behind. Today I decided to chronograph the loads just to see the velocity I was getting. Shot 10 rounds through my Caldwell (which I'm aware is a lower end model) from 15 feet. The Sierra and XTP both averaged around 1375fps. The Speer averaged 1300fps. The difference of the Sierra and XTP was around 40fps. Not sure if that's about normal or not, but the surprise was the difference in high to low with the Speer was around 100fps but the Speer will shoot much tighter groups especially at 75 yards. I loaded all 3 at the same time on the same press and there were no die settings changed between bullets with the exception the seating plug was turned maybe 1/2 turn from bullet to bullet. When I noticed the difference, I shot another 10 shot group with the Speer and this time recorded the impact of each shot along with the velocity. I got the same variation in velocity but when a bullet varied 50-60fps over or under the average, I could see no noticeable difference in poi. I am shooting off a rest with a Red Dot Tube and granted my shooting skill makes this a very unscientific test. Is 50fps over or under the average just not enough to vary the accuracy? I found it strange that the load with the largest variance in velocity is the most accurate. And I can't figure out why one bullet has so much variance compared to the other 2. When I got home, I did check the diameters of all and they are all dead on .357" and checked about 25-30 random Speer bullets expecting to see a slight difference in diameter but everyone I checked was dead on the money. Am I just over thinking this?

I HAVE TO ROLL WITH YOU ON THIS ONE Eddie. WHILE YOUR BENCHREST SHOOTING SKILLS MAY FALL SHORT OF THE USE OF A RANSOM REST, YOUR INQUIRY TOOK A SCIENTIFIC APPROACH, WITH GOOD DATA RECORDING.........

I HAVE NO IDEA WHAT WOULD CAUSE THE VARIATION OF VELOCITY WITHIN A GROUP OF SHOTS OF THE SAME AMMO. LIKE YOU, I WOULD STRIVE FOR CONSISTENCY IN VELOCITY, TO MAXIMIZE ACCURACY----AS DETERMINED BY GROUP SIZE.....

IT IS COUNTERINTUITIVE TO DISCOVER THAT THE AMMO THAT EXHIBITED THE LARGEST VARIATION IN VELOCITY, SHOT THE TIGHTEST GROUPS. I CAN'T CONJURE UP ANY POSSIBLE EXPLANATION.......
__________________
'Nam 1968-69.DAV,VFW,NRA Inst.
Reply With Quote
  #4  
Old 09-29-2018, 01:20 AM
BLUEDOT37's Avatar
BLUEDOT37 BLUEDOT37 is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2012
Location: N.E. OKLA.
Posts: 4,105
Likes: 3,259
Liked 4,247 Times in 1,799 Posts
Default SD/ES -vs- accuracy/grouping

Quote:
Originally Posted by Eddietruett View Post
The Sierra and XTP both averaged around 1375fps. The Speer averaged 1300fps. The difference of the Sierra and XTP was around 40fps.
Not sure if that's about normal or not...
The HDY XTP & the Sierra bullets are cup and core bullets; hard copper jacketed bullets. The Speer bullets is essentially a high quality plated (electro-chemically bonded) bullet & are slightly softer giving them a bit more barrel friction thus slightly slower velocities. Ordinary plated (economy) bullets are the slowest of all typical bullet types.

I've read several articles in Handloader magazine that noted ES/SD had little to no effect of grouping/accuracy. In fact in one test (45ACP) I remember the load that had the highest ES, & SD of the handloads tested, had the smallest standard group deviation. (See pink highlighted data below.)

.



.
__________________
► Caution: Slippery when wet ◄

Last edited by BLUEDOT37; 09-29-2018 at 01:27 AM. Reason: .add pic
Reply With Quote
  #5  
Old 09-29-2018, 01:53 AM
rwsmith's Avatar
rwsmith rwsmith is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2012
Location: (outside) Charleston, SC
Posts: 25,615
Likes: 30,928
Liked 22,159 Times in 10,789 Posts
Default The difference between...

The difference in time that the bullet spends in the air at 75 yard is only about 100th of a sec between 1300 and 1400 ft/sec. There are other variables.... air density, humidity, temperature wind speed, aerodynamics of the bullet, barrel harmonics and about anything else you could think of that can affect accuracy as much as a difference in velocity.
__________________
"He was kinda funny lookin'"

Last edited by rwsmith; 09-29-2018 at 01:54 AM.
Reply With Quote
  #6  
Old 09-29-2018, 02:10 AM
Twoboxer's Avatar
Twoboxer Twoboxer is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Mar 2012
Location: Eastern Pennsylvania
Posts: 931
Likes: 273
Liked 619 Times in 340 Posts
Default

At 75 yds from a rest, believe the paper.

Apparently your firearm is quite willing to put those different MVs out at the same (or compensating) launch angles. And the distance involved is too short for the vertical spread from that difference in MV to show up on paper.

You might want to verify that any modest differences in recoil don't change your results too much when shooting free hand.
Reply With Quote
The Following User Likes This Post:
  #7  
Old 09-29-2018, 02:32 AM
DWalt's Avatar
DWalt DWalt is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2009
Location: South Texas
Posts: 23,007
Likes: 2
Liked 13,895 Times in 7,681 Posts
Default

Part of the issue of which load shoots better is how "accuracy" is measured (it's not really accuracy but precision). Let's just call it grouping.

Firing a few 5-shot groups will tell you nothing, as the statistical variation in extreme spread (ES) is quite high among 5-shot groups. Extensive computer statistical analysis establishes that larger groups (10 shots or more per group) have much less variation in ES between groups. Second, taking the average of the ESs of multiple groups is even better. The most efficient measure of grouping is to fire at least five (more is better) 10-shot groups and take the arithmetic average of the five (or more) ESs as the grouping performance measurement. By doing that, the Standard Deviation of the average ES will be 5% or less of the mean ES. I doubt if many shooters would want to go to that length, but I assure you that it is necessary if you truly want to make a valid comparison between the grouping performance of two different loads. It goes without saying that the gun and the method of firing (including distance) must be the same for all groups fired.

Last edited by DWalt; 09-29-2018 at 02:35 AM.
Reply With Quote
  #8  
Old 09-29-2018, 06:48 AM
Eddietruett Eddietruett is online now
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2016
Location: South Carolina
Posts: 683
Likes: 329
Liked 1,165 Times in 364 Posts
Default

Quote:
Originally Posted by BLUEDOT37 View Post
The HDY XTP & the Sierra bullets are cup and core bullets; hard copper jacketed bullets. The Speer bullets is essentially a high quality plated (electro-chemically bonded) bullet & are slightly softer giving them a bit more barrel friction thus slightly slower velocities. Ordinary plated (economy) bullets are the slowest of all typical bullet types
.
That makes perfectly good sense. Didnít realize makeup of the Speer was different. Iím always tinkering and to me thatís what makes reloading fun. I had read articles about plated bullets being the slowest but until I did some playing around, didnít realize just how much slower some could be. Thatís what made me switch to HyTek Coated lead for most of my shooting. Just as clean, more accurate at least for me and cheaper. Another eye opener was to find tha while staying slightly under max published loads that I can get as much velocity out of a 180gr Coated Lead Bullet as I can with a 158gr Jacketed Bullet. I would have never guess that the friction of a plated bullet would drag it down so much when compared to Costed Cast.
Reply With Quote
  #9  
Old 09-29-2018, 07:15 AM
Forrest r Forrest r is offline
Member
 
Join Date: Feb 2007
Location: Ohio
Posts: 1,062
Likes: 19
Liked 916 Times in 412 Posts
Default

Spend a little time playing with a ballistic's calculator. You'll find that handgun ammo/ballistics at close range is extremely forgiving.

Your groups will be affected more from the slower bullets/dwell time/recoil. Typically the slower bullets hit higher in the group.

Example:
Junk mixed 44mag cases testing home swaged bullets. The "high" bullet hole in the group was the 1072fps.
Reply With Quote
The Following User Likes This Post:
  #10  
Old 09-29-2018, 08:43 AM
F75gunslinger's Avatar
F75gunslinger F75gunslinger is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Oct 2014
Location: South of Rochester , NY
Posts: 1,045
Likes: 65
Liked 1,074 Times in 459 Posts
Default

I would say that while a smaller standard deviation in velocities is something to strive for, it may not make as much difference when it comes to accuracy ( to a certain point of course ). Once you find a bullet that your gun likes and the right velocity range , a little bit either way may not be as important. The proof is on the paper, right ?
__________________
1st smiles,lies.Last,gunfire.
Reply With Quote
  #11  
Old 09-29-2018, 11:04 AM
jim lock jim lock is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Sep 2009
Posts: 128
Likes: 12
Liked 97 Times in 40 Posts
Default

Your reloading process seems good. The chrono. may be an issue. try to make sure it didn't move, change the distance, could be something simple.
Reply With Quote
  #12  
Old 09-29-2018, 11:07 AM
Eddietruett Eddietruett is online now
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2016
Location: South Carolina
Posts: 683
Likes: 329
Liked 1,165 Times in 364 Posts
Default

Quote:
Originally Posted by F75gunslinger View Post
I would say that while a smaller standard deviation in velocities is something to strive for, it may not make as much difference when it comes to accuracy ( to a certain point of course ). Once you find a bullet that your gun likes and the right velocity range , a little bit either way may not be as important. The proof is on the paper, right ?
Thatís the way Iím seeing it and I donít plan on changing anything. It will be my deer and coyote load based on the accuracy. My problem is Iím such a perfectionist that I want to figure out why one bullet varies more than the other 2 with everything else being equal.
Reply With Quote
  #13  
Old 09-29-2018, 12:57 PM
elpac3's Avatar
elpac3 elpac3 is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Apr 2012
Location: Mpls, Minnesota
Posts: 630
Likes: 80
Liked 549 Times in 240 Posts
Default

I seem to remember that if you want to minimize variations when running a chrono on a revolver to always fire from the same chamber as there will be minor differences between chambers. This is one of the reasons manufacturers use a closed breech test barrel for p&v testing.
Reply With Quote
The Following User Likes This Post:
  #14  
Old 09-29-2018, 01:21 PM
crstrode's Avatar
crstrode crstrode is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Oct 2009
Location: Spokane, WA
Posts: 186
Likes: 123
Liked 283 Times in 109 Posts
Default

Quote:
Originally Posted by DWalt View Post
Part of the issue of which load shoots better is how "accuracy" is measured (it's not really accuracy but precision). Let's just call it grouping.

Firing a few 5-shot groups will tell you nothing, as the statistical variation in extreme spread (ES) is quite high among 5-shot groups. Extensive computer statistical analysis establishes that larger groups (10 shots or more per group) have much less variation in ES between groups. Second, taking the average of the ESs of multiple groups is even better. The most efficient measure of grouping is to fire at least five (more is better) 10-shot groups and take the arithmetic average of the five (or more) ESs as the grouping performance measurement. By doing that, the Standard Deviation of the average ES will be 5% or less of the mean ES. I doubt if many shooters would want to go to that length, but I assure you that it is necessary if you truly want to make a valid comparison between the grouping performance of two different loads. It goes without saying that the gun and the method of firing (including distance) must be the same for all groups fired.
I almost fell outta my chair as I was reading this . . . because it is gospel. By the time enough data is generated for a good result, the gun will have been worn to the point that it actually shoots differently - go figure.

Reminds me of slogging through mountains of data writing calculations for nuclear safety system setpoint uncertainty calculations - but that is another story.
Reply With Quote
The Following User Likes This Post:
  #15  
Old 09-29-2018, 01:26 PM
mtgianni mtgianni is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Feb 2007
Location: SW MT
Posts: 3,472
Likes: 2,006
Liked 1,921 Times in 1,048 Posts
Default

A long gone shooter I had more than 100% confidence in spoke about barrel node vibration. His claim was that it was most accurate in 800 fps increments with the 1/2 nose being almost as accurate.
It follows that the most accurate loads would be at 800, 1600, 2400 and 3200 fps and near them 1200, 2000, and 2800 fps.
Recognize anything familiar about the loaded velocities for many hunting loads? This would cause that loads outside these velocities with closer extreme spreads to have a larger group than those with a larger spread at those velocities. That was what I could gather from his thoughts which were at a far advanced level than mine.

Also as another late friend asked " When did a group become less than 10 shots?"
__________________
Front sight and squeeze
Reply With Quote
  #16  
Old 09-29-2018, 01:41 PM
rwsmith's Avatar
rwsmith rwsmith is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2012
Location: (outside) Charleston, SC
Posts: 25,615
Likes: 30,928
Liked 22,159 Times in 10,789 Posts
Default Now that's a question......

Are you using brass from the same lot? I use range brass because I'm not perfectionist enough to sort them all out.
__________________
"He was kinda funny lookin'"
Reply With Quote
  #17  
Old 09-29-2018, 01:48 PM
BE Mike's Avatar
BE Mike BE Mike is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Sep 2003
Location: Indiana
Posts: 2,224
Likes: 648
Liked 1,448 Times in 676 Posts
Default

Bullseye, now precision, pistol shooters have known for a long time that low standard deviation often doesn't equate to small groups. The only way to find out if a pistol load will group well at 50 yards is to use a machine rest or something similar. The chronograph is mainly used to achieve a certain velocity.
Reply With Quote
  #18  
Old 09-29-2018, 04:30 PM
DWalt's Avatar
DWalt DWalt is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2009
Location: South Texas
Posts: 23,007
Likes: 2
Liked 13,895 Times in 7,681 Posts
Default

Quote:
Originally Posted by mtgianni View Post
A long gone shooter I had more than 100% confidence in spoke about barrel node vibration. His claim was that it was most accurate in 800 fps increments with the 1/2 nose being almost as accurate.
It follows that the most accurate loads would be at 800, 1600, 2400 and 3200 fps and near them 1200, 2000, and 2800 fps.
Recognize anything familiar about the loaded velocities for many hunting loads? This would cause that loads outside these velocities with closer extreme spreads to have a larger group than those with a larger spread at those velocities. That was what I could gather from his thoughts which were at a far advanced level than mine.

Also as another late friend asked " When did a group become less than 10 shots?"
That is essentially true, but the barrel length to get on the right part of the vibration node as the bullet leaves it depends on several factors. Some bench rest shooters believe that the best grouping performance of a rifle is obtained at a barrel length of approximately 20".
Reply With Quote
  #19  
Old 09-29-2018, 04:35 PM
DWalt's Avatar
DWalt DWalt is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2009
Location: South Texas
Posts: 23,007
Likes: 2
Liked 13,895 Times in 7,681 Posts
Default

"I almost fell outta my chair as I was reading this . . . because it is gospel. By the time enough data is generated for a good result, the gun will have been worn to the point that it actually shoots differently - go figure."

Not really. Only 50 shots for any given load/gun combination will provide highly reliable grouping performance information that cannot be obtained in any other way. Most so-called Experts have no concept of what statistical analysis involves. But they love to give their opinions anyway.

Last edited by DWalt; 09-30-2018 at 02:04 AM.
Reply With Quote
  #20  
Old 09-29-2018, 04:55 PM
WR Moore WR Moore is offline
Member
 
Join Date: Oct 2006
Posts: 3,520
Likes: 139
Liked 1,565 Times in 887 Posts
Default

If you're looking for statistical significance, you need at least 20 trials with each load.

Unless you're talking waaaaay out yonder, small velocity variation and accuracy aren't necessarily paired. Now, out yonder, velocity variation can cause significant vertical spread. At 1000 yards, 100 f/s difference can cause a vertical spread measured in feet.

Back when my eyes were young, I compared factory .44 Magnum to my handloads. I didn't have a chrono, but was well aware I wasn't getting factory velocity. At 100 yards, factory did 14 inch groups, the handload 7 inch groups. Wasn't a hard decision and I never bounced a bullet off a deer. I now have a chrono, the handloads run bout 1200 f/s for a 240 gr Remington JHP. No factory to test.

Last edited by WR Moore; 09-29-2018 at 04:58 PM.
Reply With Quote
The Following User Likes This Post:
  #21  
Old 09-29-2018, 05:09 PM
Nevada Ed's Avatar
Nevada Ed Nevada Ed is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Nov 2012
Location: Reno Nv
Posts: 6,961
Likes: 272
Liked 4,032 Times in 2,095 Posts
Default

I noticed with my pistols and revolvers and my 686 6" that maximum
fps does not always give top accuracy or that a small ES of a load
mean it will be the most accurate load out of my test groups.

ES is what it is and the bullets do their thing per the weapon used.
I no longer give a small ES the nod , just as long as it is under 150fps for a six to ten grouping.

Mostly with the copper jackets........
Lead seems to behave itself in the 686, better than the jacket bullets,
for some odd reason but I generally am shooting the same lot or brand.

Different copper bullets will be a little different do to shape, Ojive, length and maybe Dia.
My 9mm likes the Speer TMJ but my 686 likes the XTP over the Sierra and Speer jacketed bullets.
Out of the 6" tube, the 158gr XTP gets 1340fps with a +/- ES of 67.
At 1274fps I can cut the group size in half but I have a ES of 81.

My old load with a 158 out of my M19 with Unique was slower but killed deer.
I later found out that the Speer 158JSP #4217 was clocking 1230fps.

Numbers are nice to have but it can't compare to a picture of a tight group
no matter what the ES is.
Good shooting.
Reply With Quote
The Following User Likes This Post:
  #22  
Old 10-01-2018, 12:57 AM
Eddietruett Eddietruett is online now
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2016
Location: South Carolina
Posts: 683
Likes: 329
Liked 1,165 Times in 364 Posts
Default

Quote:
Originally Posted by Nevada Ed View Post

Numbers are nice to have but it can't compare to a picture of a tight group
no matter what the ES is.
Good shooting.
I've noticed a lot of the same as you have found.
I have 2 model 686's. One has a 8 3/8" and other a 7"
Both set up with Simmons red dot tubes.
The 8 3/8 loves HyTek Coated Cast and will shoot Jacketed almost as well.
The 7" will shoot jacketed as well as the 8 3/8" but don't ask it to do anything accurate with a lead bullet. Groups at 75 yards are at least 50% larger than the longer barrel. Velocity is about the same with both length barrels with the longer giving on average 50-60 fps more.
I know the first thing some will ask is did you slug barrels and measure throats. The answer is no to both since I don't do any casting and sizing, I work with what is easily available. Why does one gun shoot jacketed sized .357 and Cast sized .358 equally as well and the other gun only shoots jacketed that is sized at .357 well. I don't really know and it really doesn't matter since I don't see any easy way to change it. What does work great for me is when I go to my stand, I can load the 8 3/8 with 180gr Cast for Hogs and keep the 7" loaded with 158 jacketed for deer and coyotes. So I really have the best of both worlds and since they both will group something well, the spread numbers after reading all of the information that has been replied, will not be a concern.
Reply With Quote
  #23  
Old 10-05-2018, 08:16 AM
10mm_Shooter's Avatar
10mm_Shooter 10mm_Shooter is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Jun 2009
Posts: 58
Likes: 0
Liked 27 Times in 17 Posts
Default

I'm a numbers person too I like to see low ES, low SD and ES vs mean velocity in my handloads. But as others have mentioned..... what really matters is what your target looks like. So many other variables. Dont get too deep in the woods.. Again performance on the target is what matters.
Reply With Quote
  #24  
Old 10-05-2018, 08:50 AM
stansdds stansdds is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Apr 2007
Location: Virginia
Posts: 691
Likes: 68
Liked 598 Times in 349 Posts
Default

Accuracy is king, but it is really nice when accuracy is excellent and velocity is very consistent. Must the two go hand-in-hand? At 100 yards or greater, yes. At 50 yards or closer, does not matter nearly as much. A wide ES can indicate inconsistent ignition of the powder or variations in powder charge.
Reply With Quote
  #25  
Old 10-05-2018, 09:51 AM
mike campbell's Avatar
mike campbell mike campbell is offline
Member
Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question Consistant Velocity vs Accuracy Question  
Join Date: Dec 2014
Location: rural western NY
Posts: 443
Likes: 49
Liked 1,025 Times in 241 Posts
Default

Quote:
Originally Posted by Eddietruett View Post
.... And I can't figure out why one bullet has so much variance compared to the other 2. When I got home, I did check the diameters of all and they are all dead on .357" and checked about 25-30 random Speer bullets expecting to see a slight difference in diameter but everyone I checked was dead on the money. Am I just over thinking this?
You're nibbling around the edges of the issue here .... it's consistent pressure that translates to consistent velocity. Pressure consistency is correlated to bullet pull, which is affected by case wall thickness, crimp and, yes, bullet diameter, both absolute and relative (to chamber diameter).
What does "dead on .357" mean?

If one uses calipers and not a micrometer, they really have do idea. Significant bullet diameter differences are measured in ten thousandths of an inch. A caliper can read ".357 dead on" with a bullet that is .3565 and another that is .3574 ... practically .001" different in reality.

Stack tolerances on brass thickness, crimp variance due to slight variation in case length, and true bullet diameter and ES of 100fps is very believable. As to the real world significance of such ES with respect to accuracy (precision) ... the paper doesn't lie.

IMO, statistical evaluation of handgun accuracy is navel-gazing. I can shoot 2, 10-shot groups with each different load from a Ransom rest and make a $100 bet on which will be the most accurate in that gun forevermore.
__________________
Carry.."hope" isn't a strategy
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Velocity Question AZ_M&P Reloading 7 05-04-2015 05:56 PM
Rifle Velocity Question? walkinghorse The Lounge 19 01-08-2015 06:08 PM
Velocity Question RDub Reloading 4 03-26-2011 09:02 PM
Excellent Article:Testing .22 ammo velocity/accuracy Steve02C5 Smith & Wesson M&P 15-22 2 09-25-2010 04:44 PM
The .38 Special, Loading for Accuracy and Velocity, and Differences in Barrel Length semperfi71 Reloading 2 05-01-2010 02:43 PM

Powered by vBadvanced CMPS v3.2.3
smith-wessonforum.com tested by Norton Internet Security smith-wessonforum.com tested by McAfee Internet Security

All times are GMT -4. The time now is 10:57 PM.


Search Engine Optimisation provided by DragonByte SEO v2.0.42 (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
© S-W Forum, LLC 2000-2018
Smith-WessonForum.com is not affiliated with Smith & Wesson Holding Corporation (NASDAQ Global Select: SWHC)