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Old 08-11-2017, 03:09 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Default Interesting finding on velocity difference between 158 grain Zero bullets.

The other day I finally got to go to the range and play a little and try out some new-to-me Zero 158 grain JHP bullets and brought along my chronograph and I also brought along some rounds loaded with some Zero 158 grain JSP bullets I had bought a year or so ago. Besides the different bullets, everything else was the same as far as powder charge and primers and both batches were loaded on the same day from the same lot of powder. I figured that since the shape of the bullets were pretty close besides the fact that one was a hollow point and the other was a soft point, but I did see a significant velocity difference. Here is what they were loaded with:

Pistol: S&W 627 Pro (4" barrel)
Bullet: Zero 158 grain JSP or 158 grain JHP
Case: assorted
Primer: CCI 550
Powder: Alliant 2400, 14.5 grains
Both were loaded and crimped in the crimp serrations

The Zero 158 grain JSP bullets averaged 1037 fps with a SD of 17. The Zero 158 grain JHP loads averaged 1114 fps with a SD of 22.

The JHP bullets averaged a good bit faster than the JSP bullets, which surprised me. The SD also was higher, but not a whole bunch more.

I also brought along my old Beretta M9 and a couple of different loads to run across the chrono too. The bullets were some Zero 147 grain JHP bullets and some MBC 124 grain coated "Small Ball" bullets. I had gotten the Zero bullets when I had ordered the 158 grain JHP bullets for kicks and giggles to try out and I had bought the Small Ball bullets the last time I had ordered from MBC. The loads for them and the results are as follows:

Pistol: Beretta M9 (4.9" barrel)
Bullet: Zero 147 grain JHP
Case: assorted
Primer: CCI 500
Powder: Longshot, 4.4 grain
Avg velocity: 889 fps
SD: 9

Bullet: MBC 124 grain Hi Tek coated "Small Ball"
Case: assorted
Primer: CCI 500
Powder:Longshot, 5.0 grains
Avg Velocity: 1061 fps
SD: 14

Both of those loads were fun to shoot, with pretty mild recoil and cycled well and grouped the cases pretty much in one area. And looking at the primers, they were not nearly as hot as the factory cases I also picked up at the range and were not remotely close to being flattened. They were some fun rounds to shoot.

Finally, I also brought along my 629-3 Classic and some light loads for it and ran them across the chrono.

Pistol: 629-3 Classic (6 1/2" barrel)
Bullet: Bayou Bullets 240 grain Hi-Tek coated SWC
Case: FC
Primer: CCI 350
Powder: Alliant Unique, 7.1 grains
Avg Velocity: 876 fps
SD: 12

These were also a pleasure to shoot and I had fun running 100 rounds of this load. They also seemed to shoot pretty clean for a Unique load also and the pistol isn't too terribly dirty.

The conclusion of all this? I had a good time playing at the range and surprisingly, it didn't rain until I was driving home. And I figured I would share a little number info on what I saw with these loads at the range with my fellow reloading friends here on the forums.
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Old 08-11-2017, 08:43 AM
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Honestly, I would not consider those 158 gr. figures significantly different. It's not unusual to see a less-than-80'/second shot to shot variance, and hardly more significant to see that difference in an average, unless the average includes at least several hundred rounds. In fact, they are so close that it would not surprise me at all to see the numbers reversed if you ran the same comparison again.
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Old 08-11-2017, 10:22 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Statistically, if that data is from only 6 rounds of each, the 1037 and 1114 means are very significantly different.

Given identical primers, powder and charge weights one wonders why one is likely higher pressure than the other. Different bullet tension would be the next most logical variable.

Less likely bullet tension factor would be bullet diameter...same maker and weight, you'd expect the same diameters but maybe not. A micrometer (not calipers) would tell.

More likely tension factors would be case make and degree of crimp. Some makes will have thicker walls than others; mixed lengths can have some heavily crimped, others not at all.
Bottom line: just one of those things that would make me say "hmmmm."
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Old 08-11-2017, 11:25 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Those were actually averages from around 14-16 rounds, not 6 or 8. I had a few I had to cull because of bad readings. And I found that the 2400 was shooting kind of dirty too, with a little unburned powder left in the cases, so I think that some unburned powder was also traveling out of the barrel too and possibly interfering with the reading. One string I shot I had to cull because over half the readings were a little more than 1/2 the expected velocity in the 600-650 ft/sec range. When I backed the chrono further out around 3 feet those went away.

BTW, I'm not trying to be overly scientific with this or trying to make some competition ammo or anything. I'm just out having fun and putting rounds on target. And sharing some info here, as many times I see people post up stuff here and assume some velocity for their load with no scientific basis to establish real world results. I think that next time I play with these I will use Accurate #9 instead of 2400 for my powder, as I've found it burns more completely than 2400. And I will bring my Rossi 92 to compare the ammo betwen a short barrel pistol and a 20" barrel rifle.
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Old 08-11-2017, 11:32 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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How far was the chrono from the muzzle for the data you are keeping?
3 feet?
Or 3 feet more from initial placement of say 10 feet?
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Old 08-11-2017, 11:56 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Yeah, 3 feet from the original placement, which was around 10 feet or so.
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Old 08-11-2017, 12:19 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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I agree, it's fun to get out and play at the range

I'm trying to get out later this afternoon

I really don't think you're getting too much velocity differences.

I haven't really researched the topics much....but your 2 bullets do have different sectional densities and different ballistic coefficients

How long are the 2 bullets?
If same COL
Is one seated deeper in case than the other?
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Old 08-11-2017, 12:25 PM
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I expect the HP would be longer than the SP. If so, and you used the same COL, then the HP would have a smaller volume for the powder. This would increase velocity slightly...

Wil
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Old 08-11-2017, 01:03 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Quote:
Originally Posted by muddocktor View Post
The Zero 158 grain JSP bullets averaged 1037 fps with a SD of 17. The Zero 158 grain JHP loads averaged 1114 fps with a SD of 22.
The JHP bullets averaged a good bit faster than the JSP bullets, which surprised me. The SD also was higher, but not a whole bunch more.
Quote:
Originally Posted by mike campbell View Post
Statistically, if that data is from only 6 rounds of each, the 1037 and 1114 means are very significantly different.
Given identical primers, powder and charge weights one wonders why one is likely higher pressure than the other. Different bullet tension would be the next most logical variable.
Less likely bullet tension factor would be bullet diameter...same maker and weight, you'd expect the same diameters but maybe not. A micrometer (not calipers) would tell.
More likely tension factors would be case make and degree of crimp. Some makes will have thicker walls than others; mixed lengths can have some heavily crimped, others not at all.
Bottom line: just one of those things that would make me say "hmmmm."
I donít put much confidence into 5-6 shot sample sizes, but the OP used 14-16 rounds. With that sample and SDs of 17 and 22 respectively, 1,037 fps is significantly lower than 1,114 fps.
Generally speaking with an average velocity of 1,037 fps and a SD of 17, youíd expect 67 of the rounds fired from a 100 round box to have a velocity within +/- 1 SD. In this case, between 1,020 fps and 1,054 fps. About 95 of the rounds from a 100 round box would fall between 1,003 fps and 1,071 fps, and essentially all of the rounds in the box would call between 986 fps and 1,088 fps. In short the expected extreme spread is +/- 3 SD, or 6 SD in total (17 fps x 6 = 102 fps extreme spread).
Similarly, for the 1,114 fps load with the SD of 22, youíd expect 67 of the rounds fired from a 100 round box to have a velocity within +/- 1 SD. In this case, between 1,092 fps and 1,136 fps. About 95 of the rounds from a 100 round box would fall between 1,070 fps and 1,158 fps, and essentially all of the rounds in the box would call between 1,048 fps and 1,180 fps. The expected extreme spread is again +/- 3 SD, or 6 SD in total (22 fps x 6 = 132 fps extreme spread).
There is an overlap of 40 fps in the 3rd SD between the fastest JSP rounds and the slowest JHP rounds, but that represents only about 2% of the total rounds fired.
The JHPs are significantly faster, at least at a 95% confidence level.
----
Itís hard to say exactly why, but there are some easily identifiable suspects, even if exactly the same powder charger, crimp, etc was used with both loads.
The hollow point displaces some lead, which has to go somewhere if both bullets still weigh 158 grains.
If the nose profile is the same, then the weight displaced from the hollow point ends up being in the base of the bullet, where it not only reduces the case volume under the bullet (if the same OAL is used) but also increases the bearing surface of the bullet, and both of those will increase the pressure while the rifling engraves the bullet. The longer bearing surface would also very slightly increase friction in the bore, but would also very slightly reducing the amount of gas that gets past the bullet in the throat and in the barrel, so itís a bit of a wash after the initial pressure effects the charge ignites until itís fully engraved in the rifling in the barrel.
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Old 08-11-2017, 01:31 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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I agree with the posters above who suggest the JHP bullet is longer and would tend to increase velocity(all else being equal). Powders like 2400 and Accurate #9 perform best with full case loads. Reduced loads don't fully burn and leave powder granules. I experienced the same thing 20+ years ago.

I'll share another lesson I got shooting 9mm handloads using mixed brass. I was getting 4 to 6" groups at 15 yds. off bags with my Beretta M9. I got much better groups using only one brand of brass....doesn't matter what brand as long as they are the same. Try it...doesn't cost you.

Have fun.
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Old 08-11-2017, 01:50 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Default Am I reading something wrong...

Aren't all of those velocities low for that load???? 14.5 grains of 2400 with a 158 gr jacketed should be going about 1200 ft/sec or better???
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Old 08-11-2017, 03:00 PM
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Same weight bulllets, the JHP will have a slightly longer bearing surface. IT doesn't take much to up pressures & increase vel a little bit.
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Old 08-11-2017, 03:03 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Quote:
Originally Posted by Will2 View Post
I expect the HP would be longer than the SP. If so, and you used the same COL, then the HP would have a smaller volume for the powder. This would increase velocity slightly...

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Old 08-11-2017, 03:07 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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I just took a few pics of the Zero bullets to post here. Looking at them, the distance from the base of the bullet to the crimp groove/serrations is very nearly the same on both bullets, so case volume differences with the bullets in the loaded condition are minimal, but might help account for the differences in velocity. The JHP bullet is longer, .650 inches versus .635 inches for the JSP bullet. Both bullets show a diameter of .357 according to my dial calipers. I'm thinking the velocity differences between them might also be tied into the bullet configuration above the crimp groove more than anything else, but that is just a guess. BTW, with revolver loads, I load to the crimp groove and not OAL.

Here are the pics. The JSP bullet is the one in the middle and the JHP bullets are on each side of it.



RW, the velocities might seem low at first glance, but you are comparing apples and pears as far as barrel length goes. My 627 Pro has a 4" barrel. Looking at the Alliant site, they are showing a max load of 14.8 grains of 2400 for 1265 fps, but that is with a 10" barrel. That 6" of extra barrel length can account for the different velocities.
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Old 08-11-2017, 03:12 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Next time I do some experimenting with them I will use just 1 brand of cases, S&WIowegan. That is a good point you brought up and takes another variable out. I have some brand new Starline brass sitting in a box I can put into service when I do the next round of playing with Accurate #9 instead of 2400.
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Old 08-11-2017, 05:21 PM
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Quote:
muddocktor wrote:
The Zero 158 grain JSP bullets averaged 1037 fps ... 158 grain JHP loads averaged 1114 fps....
Did you weigh the bullets before loading them to verify that they were both the same weight?

Just because they are both in the 158 grain class doesn't mean they both weighed exactly 158.0 grains and if one type was even a couple grains heavier than the other, that would be sufficient to explain the difference.
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Old 08-11-2017, 09:44 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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No, I did not weigh them before. But I just grabbed a sample bullet from each box and weighed them on my powder scale. And in both samples, they each weighed 158.4 grains. I'm sure if I grabbed 10 of each I would see some variation, but from that simple grab-n-weigh I am satisfied that they are essentially the same weight.
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Old 08-11-2017, 11:30 PM
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Not to beat a dead horse . . . well, it is fun I guess . . . in addition to the JHP being longer I'd guess your seating plug might hit the JHP higher on the ogive. At least it looks that way from your photos.

That would seat the JHP even deeper.
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Old 08-12-2017, 12:04 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Quote:
Originally Posted by Twoboxer View Post
Not to beat a dead horse . . . well, it is fun I guess . . . in addition to the JHP being longer I'd guess your seating plug might hit the JHP higher on the ogive. At least it looks that way from your photos.

That would seat the JHP even deeper.
I set the seating plug for the bullet I'm loading. In other words, I adjust it to set the bullet to where the crimp is applied in the crimp groove/cannelure on whichever bullet I am loading. I've been reloading straight wall pistol cartridges since the mid 70's and for cartridges such as 38/357 and 44 Mag. I've always set the seating depth so that the roll crimp is in the crimp groove or cannelure and don't worry about OAL as long as they fit in the cylinder.
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Old 08-12-2017, 12:48 AM
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Default Could somebody please address this question.....

I asked it above but I think it was blown out of the water by the bearing length theory.

"Aren't all of those velocities low for that load???? 14.5 grains of 2400 with a 158 gr jacketed should be going about 1200 ft/sec or better???"
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Old 08-12-2017, 02:05 AM
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Looking at that picture of the two bullets, makes me think that
they are close enough to not make that big a deal out of fps
if the same identical components were used.
However you did say mixed brass.......right ?

One thing about the fps, though.
It does seem a little low to me since 14.5 grs of 2400 with a 158 XTP.......
out of my 686 6" and a cci primer does 1274fps with R-P cases.
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Old 08-12-2017, 02:09 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Quote:
Originally Posted by Nevada Ed View Post
Looking at that picture of the two bullets, makes me think that
they are close enough to not make that big a deal out of fps
if the same identical components were used.
However you did say mixed brass.......right ?

One thing about the fps, though.
It does seem a little low to me since 14.5 grs of 2400 with a 158 XTP.......
out of my 686 6" and a cci primer does 1274fps with R-P cases.
Thanks for confirming that. I was really scratching my head. Now does anybody have an explanation as to why the velocities seem low??? I didn't quite understand the distance between the muzzle and chrono. How far was is??? I'm starting to think that the chrono might be hinky.
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Old 08-12-2017, 03:18 AM
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I can't speak to much of the OP's test. Except it sounds like a good day at the range! But I can speak to the "dirty" 2400. I have been shooting 2400 since the mid 1960s. With loads that were Phiffle to more powder than most sane people would shoot. From 38 spc. to 44 mag to reduced rifle cast loads and I have never been able to not have powder(or as I like to call it---Gravel) left on and in the gun and surrounding area. Once, after shooting several hundred 38/357 loaded with 2400 on a concrete shooting area, it was necessary to sweep the area in front of my shooting spot because it was like someone had sanded that area and it was slippery. Sort of like walking on marbles or small ball bearings.
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Old 08-12-2017, 03:34 AM
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Quote:
Originally Posted by hdwhit View Post
Did you weigh the bullets before loading them to verify that they were both the same weight?

Just because they are both in the 158 grain class doesn't mean they both weighed exactly 158.0 grains and if one type was even a couple grains heavier than the other, that would be sufficient to explain the difference.
Not likely. Measure the actual bearing surface, has far more affect than even oal.
I just ran some liars using bayou 145gr RN 9mm. My std competition bullet is a 146gr RN. The bayou has no lube groove, solid shank. I get the same vel as the heavier bullet, both Hi-tell costed, same oal, but the bayou takes 3/10gr less powder to get there. The solid shank s offer far more bearing surface, higher vel.
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Old 08-12-2017, 08:52 AM
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Quote:
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.......... I didn't quite understand the distance between the muzzle and chrono. How far was is??? I'm starting to think that the chrono might be hinky.
Rw
My chronolograph instructions state to set the 'chrono' from 5 feet to 10 feet from muzzle for pistols......10 to 15 for rifles
This is to eliminate muzzle blast from interfering with the readings.

The OP realized that could have been an issue and moved the 'chrono' out more.
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Old 08-12-2017, 10:09 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Originally Posted by rwsmith View Post
I asked it above but I think it was blown out of the water by the bearing length theory.

"Aren't all of those velocities low for that load???? 14.5 grains of 2400 with a 158 gr jacketed should be going about 1200 ft/sec or better???"
RW, I addressed your question in post #14, below the pics of the bullets. According to Alliant's online data, a max charge of 14.8 grains of 2400 with them using the Speer 158 grain GDHP bullet is good for 1265 fps velocity. But they are using a 10" test barrel. And they don't specify which gun they are testing with, so we don't know if it is a revolver or a non-vented test setup. My 627 Pro has a 4" barrel and you know that a shorter barrel such as that will lose quite a bit of velocity as compared to a 10" barrel. And that is especially true when you get to the slower magnum powders such as 2400 or H110. When shooting these, I was seeing quite a nice ring of fire coming out of the barrel at times, indicating to me that as the bullet was exiting the barrel I still had some powder combustion going on.

And forestswin is exactly right why I had to move the chrono out some. I was getting interference from the unburned combustion products leaving the barrel with the 2400 loads from my 627. The 9MM and the 629 I also shot that day had not given me any problems at the same distance to the chrono, but I was using faster powder in those loads and they weren't kicking out unburned powder and/or carbon like the 2400 loads were. 2400 reminds me a lot of IMR4227 in the way it burns dirty and leaves unburned powder and stuff around the bench.
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Old 08-12-2017, 10:43 AM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Thanks for clearing me up. That would explain it, so back to the original question.
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  #28  
Old 08-12-2017, 12:42 PM
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Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets. Interesting finding on velocity difference between 158 grain Zero bullets.  
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Originally Posted by rwsmith View Post
Aren't all of those velocities low for that load???? 14.5 grains of 2400 with a 158 gr jacketed should be going about 1200 ft/sec or better???
rw
this is the original question? correct?
Speer #8 has data using a S&W Model 27 6 inch
and for 2.5" barreled Colt and S&W's

the bullet used for both are their 160 gr. soft point - it has a different shape than OP's bullet - but its of use in a comparison using the exact same bullet for both of their tests

6 inch data
15 grains / 1280 fps
14 grains / 1204 fps
CCI 550 magnum primers were used

2.5 inch barrel
15 grains / 1199 fps
also used CCI 550 magnum primers

from my experience....magnum primers add 50 fps in my 6 inch 686

so subtracting 50 fps
6 inch
15 grains / 1230 fps
14 grains / 1154 fps

2.5" barrel
15 grains / 1149 fps

OP used 14.5 grains and a 4 inch barrel

1037 and 1114 are a little low but
It seems to me his velocities are in the ballpark with the manuals, and considering the manuals are usually optimistic.
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Last edited by forestswin; 08-12-2017 at 12:58 PM.
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