|
|
02-21-2014, 03:39 AM
|
Member
|
|
|
Join Date: Apr 2013
Posts: 77
Likes: 19
Liked 14 Times in 7 Posts
|
|
M&P 10 Bullet Jump ?
I am getting a OAL of 2.267" from the OGIVE with a Sierra MatchKing 180 GR HPBT and a Sierra MatchKing 155 GR HPBT . The case is the Hornady Modified Case fro .308 and the Bullet Comparator and the OAL Gauge.
Any similar measurements and what bullet jump are you looking for?
I have also noticed better group with slower speeds. like around 2450-2550 fps versus 2700-2800 fps.
I guess while I am at it, I have 180 Grain 31322 lyman molds for .308. I got the guess checks. Is ball power a better idea for these loads a keeping them under 2000fps?
|
02-21-2014, 04:00 AM
|
|
Moderator SWCA Member Absent Comrade
|
|
|
Join Date: Dec 2006
Location: Northeast PA, USA
Posts: 8,877
Likes: 1,029
Liked 5,070 Times in 2,660 Posts
|
|
I don't think a ball powder will make a difference one way or another. With lead bullets I try to use faster powders which don't burn quite as hot as others in their burn rate range. The powder I usually use for lead bullets in centerfire cartridges is SR4759 but I can't find any lately. I guess I'll have to give AA5744 a try next time I load lead bullets for my 30-06 and 30-30.
__________________
Freedom is never free!!
SWCA #3437
|
02-21-2014, 08:02 AM
|
Member
|
|
|
Join Date: Jan 2012
Location: God's Country
Posts: 4,711
Likes: 1,235
Liked 3,535 Times in 1,770 Posts
|
|
SR4759 or AA5744 are both good powders for reduced load. However, rumor has it that Hodgdon is discontinuing SR4759, so either buy a bunch or skip it completely when you stumble across a cache. By the way, the reduced loads will convert your M&P 10 into a single shot.
I'm going to miss it. For over 30 years, I've worked upa reduced load for every caliber I've purchased for cheap, pain free practice. There's something about sending a 235 gr. Speer bullet from a .375 H&H downrange at 1800 fps. that just makes good sense.
I load all my AR's to mag length when first working up a load and don't worry about bullet jump. I do measure the jump with the same equipment you have simply because the experimental reloader in me needs to know it. You can also shorten your COAL and see if it improves accuracy and then match it with your next lot of bullets if it does. AR's don't seem to be as sensitive to bullet jump as are bolt guns.
|
02-21-2014, 12:02 PM
|
|
Member
|
|
|
Join Date: Feb 2006
Location: Kalif. usa
Posts: 6,836
Likes: 2,665
Liked 3,927 Times in 2,366 Posts
|
|
There is no magic distance to the rifling for best groups. Every rifle & bullet is diff. The common wisdom is to start 0.010" off the lands. Many rifles w/ magazine won;t let you get that close. So I load to mag length that functions & work with that.
__________________
NRA Cert. Inst. IDPA CSO
|
The Following User Likes This Post:
|
|
02-21-2014, 01:40 PM
|
|
US Veteran
|
|
|
Join Date: Nov 2012
Location: Reno Nv
Posts: 13,376
Likes: 3,183
Liked 12,712 Times in 5,669 Posts
|
|
My 22-250 with a 55gr Hornady and IMR 4759 gets 2750 and 4 @ .57 with a reduced load.
My 30-06 with a Hornady 100gr "Plinker" with the same powder gets 1600 fps and places 4 @ .53 at 50 yards. A great load for the wife and kids.
I also try to keep all my "Plinker Load" brass together and do NOT use it again with any high power loads, due to the way the case acts in the chamber...... per one reloading manual I read.
Hope this helped.
|
02-21-2014, 06:23 PM
|
Member
|
|
|
Join Date: Sep 2011
Location: Anaheim, Ca
Posts: 926
Likes: 204
Liked 445 Times in 243 Posts
|
|
Quote:
Originally Posted by fredj338
There is no magic distance to the rifling for best groups. Every rifle & bullet is diff. The common wisdom is to start 0.010" off the lands. Many rifles w/ magazine won;t let you get that close. So I load to mag length that functions & work with that.
|
Follow that advice.
Auto loaders are typically limited by mag length, so you can max them at that safely unless you want to single load. For bolt guns I usually start at 0.015". Some I may go down to a slight jam, but these loads are worked up very slowly as less jump = higher pressure. Also another thing with jam loads is you may pull a bullet unloading, very messy.
On the other hand I think it was Weatherby throats are so long long the bullet pretty much falls out the neck before you get close to the lands.
Also my bolt guns like around 2500fps for max accuracy. Unless you're shooting way out there, no reason for crazy speed.
|
02-26-2014, 09:04 PM
|
Member
|
|
|
Join Date: Apr 2013
Posts: 77
Likes: 19
Liked 14 Times in 7 Posts
|
|
Yes, using .012 from the lands, it is much to long for the magazine, but I am just using these for bench rest shooting anyway. SO I failed miserably and forgot to check the case in the rifle after setting up the die. It looked fine in the case gauge, but certainly not in the rifle. It jammed as soon as I released the bolt. I didn't notice the bolt wasn't closed and pulled the trigger. Click.... I couldn't pull the bolt back either, it was stuck hard. I took the rifle home and googled what to do and learned about mortaring? Basically, it said to go outside and pound the butt stock into the ground pointing the barrel up while pulling down on the charge handle. I have to tell you, I was not at all comfortable with that solution, but it did work and I am here writing about it. Are there any alternatives to this method that someone might be able to share?
|
02-26-2014, 09:06 PM
|
Member
|
|
|
Join Date: Apr 2013
Posts: 77
Likes: 19
Liked 14 Times in 7 Posts
|
|
Quote:
Originally Posted by BlueOvalBandit
Follow that advice.
Also another thing with jam loads is you may pull a bullet unloading, very messy.
.
|
And yes, it did pull the bullet and spill all that precious powder into my front lawn!
|
|
Thread Tools |
|
Display Modes |
Linear Mode
|
Posting Rules
|
|
|
|
|