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reloading for a short barrel 308 |
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Posted: January/06/2013 at 14:01 |
Alright guys need some help...
My son had his Stevens 308's barrel cut down to 16.5". When he did the accuracy with our current loads went from sub MOA to about 3 MOA. So I now need to develop a new load for it. I will be using 180Gr Nosler Partitions. The old loads used Varget. With the shorter barrel I'm thinking I'll need to go to a faster burn rate powder like H4895 or Benchmark. Who here has recipes for shorter barrel 308 loads and what are they? Thanks in advance Bud
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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cheaptrick
MODERATOR Joined: September/27/2004 Location: South Carolina Status: Offline Points: 20844 |
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How long was the barrel before, Bud? Are you saying that the same loads that shot well BEFORE the barrel was cut, won't shoot now?
I lost a little velocity when I went from 26" to 20", but I didn't loose any accuracy with the same recipe.
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If at first you don't secede...try..try again.
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Mike McDonald
Optics Journeyman Joined: September/01/2004 Status: Offline Points: 739 |
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Sure the crown is square to the bore?
try H9895 in the 39 to 40 grain range with large brass ( Hornady, Winchester, Lapua, Blackhills) and wlr primers.
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338LAPUASLAP
Optics Master Scope Swapper Joined: October/17/2009 Status: Offline Points: 2596 |
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Yeah, I'm on that train...
I would be pissed. You will not loose MOA you might loose velocity and a little distance or bullet drop but not MOA spread or roundness. I would be checking with the Smith to see what he will do for you. 13-14 inches is short for .308 16.5 is plenty depending on twist and bullet weight... |
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No one
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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id try a different bullet, the partition isnt exactly a house of fire in the accuracy dept. maybe try the accubond???
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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead" 343 we will never forget God Bless Chris Ledoux "good ride cowboy" |
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MC Escher
Optics Apprentice Joined: September/25/2012 Location: Ohio Status: Offline Points: 121 |
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I have a sneaking suspicion that eliminated several inches of barrel and the rifling that went with it means that your son's rifle will no longer stabilize as heavy a bullet as it used to.
This assumes there are no burs on the muzzle that could affect bullet flight. A very slight chamfer at the end of the bore might be helpful in that regard. |
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The older I get, the better I feel about tearing up parking tickets and cheating on my taxes.
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jonoMT
Optics Master Extraordinaire Joined: November/13/2008 Location: Montana Status: Offline Points: 4853 |
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Sounds like a bad crown.
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Reaction time is a factor...
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SVT_Tactical
MODERATOR Chief Sackscratch Joined: December/17/2009 Location: NorthCackalacky Status: Offline Points: 31233 |
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Bud I had my SPS tactical cut down to 16" and didn't loose a thing. The crown must be messed up or when they cut it maybe there is a burr in the bore, take a cotton swab and put it in the barrel and pull it out around the edges and see if it catches on anything. Otherwise the crowns messed up. I still hold the same groups in mine using varget for supersonic loads.
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"Most folks are about as happy as they make their minds up to be" - Abraham Lincoln
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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where is that thread from a while back where they cut an inch at time or something like that and reported all the data???
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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead" 343 we will never forget God Bless Chris Ledoux "good ride cowboy" |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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Sounds like something wasn't done right,Bud.
Here's a bbl length vs velocity test by gunsmith Charlie Sisk:
[ QUOTE ] For a long time I have wondered about how barrel length affected velocity. I had always been told you need a certain length barrel for certain calibers. I have read when folks compared one gun to another with different lengths but I always thought that was not an apples to apples comparision. So I did a few test myself. All these were Shilen barrels. I used the same brass through out the whole test. All weighed to with 1 grain. Bullets were tested on the Juenke machine. Powder charges were weighed to .1 grain. The same rest, chronograph, Redding press, primers all from the same lot, bullets for the same box, same lathe, same crowning tool, same cutoff tool, and each rifle done from start to finish on the same day. Ambient temperature was the same because I shoot from inside the shop. I held the rifle the same way on the rest every time. I shot ten rounds first to break in the barrel. Then cleaned with Sweets and fired one fouling shot. Then shot five rounds and took the average. I used a midrange load fron the Nosler book, not too hot but certainly not a reduced load. Here is what I got. 22-250 Hodgdon 380 34 grains Federal GM210M Remington brass 55 grain Ballistic Tip 27 inches 3469 fps 26 3451 25 3425 24 3407 56 fps from highest to lowest 270 Winchester Hodgdon 4350 54 grains Federal GM210M Winchester brass 130 grain Sierra 27 inches 3115 fps 26 3093 25 3071 24 3054 23 3035 22 3027 21 3001 114 fps from highest to lowest 300 Winchester mag Federal GM215M Winchester brass 74 grains of Reloder 22 180 grain Partition 27 inches 3055 fps 26 3031 25 3024 24 3003 23 2984 22 2960 95 fps from highest to lowest 340 Weatherby Federal GM215M 250 grain Sierra 81 grains Reloder 22 Wby brass 27 inches 2837 fps 26 2817 25 2809 24 2791 23 2777 22 2755 21 2731 106 fps from highest to lowest I think I will do a little more thinking before I recommend a barrel length in the future. What do you folks think ? Charlie Here is the info about the 338 Win and the 257 Roberts. 338 Win mag Winchester brass Federal GM215M primers Reloder 19....73 grains 250 grain Partitions 27 inches.....2806 fps 26 inches.....2787 fps 25 inches.....2761 fps 24 inches.....2743 fps 23 inches.....2716 fps 22 inches.....2697 fps 21 inches.....2676 fps 20 inches.....2656 fps 150 fps from 27 inches to 21 inches 257 Roberts Federal GM210M primers Remington brass H-4350....45 grains 120 grain Partitions 27 inches.....2860 fps 26 inches.....2834 fps 26 inches.....2815 fps 25 inches.....2815 fps 24 inches.....2798 fps 23 inches.....2775 fps 22 inches.....2760 fps 21 inches.....2739 fps 20 inches.....2717 fps 143 fps from 27 inches to 20 inches I want to test this on the next 450 Marlin I build and on a 222 Remington. If I get the same results with those, in my mind the test is over. I think this will be enough data to support the findings. Are there any folks out there who have a degree in this sort of thing ? Maybe explain how many data points would be needed to be able to say this would work with the majority of calibers ? Someone with experience in statistical(spell check) quality control ? Charlie A few weeks ago I done some testing with shortening barrels with various calibers. I just finished this test with a 300 Ultra. These loads were EXTREMELY HOT !!!!!!!!! I will not post the grains here because on the third loading the primer would fall out of the case . I never load this hot , only this time for the test. I used Remington brass, Federal GM215M primers, 220 grain round nose bullets. I used the same procedures as the last test. length.... H-4895 .....H-870 .....27 .....2740 .....3107 FPS .....26 .....2709 .....3088 .....25 .....2685 .....3062 .....24 .....2663 .....3046 .....23 .....2636 .....3018 .....22 .....2612 .....2997 H-4895 lost 128 fps H-870 lost 110 fps |
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"I ain't got time to bleed!"
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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here is one example i pulled off the net, keep in mind its a .223 not a .308 though.....
http://www.accuratereloading.com/223sb.html |
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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead" 343 we will never forget God Bless Chris Ledoux "good ride cowboy" |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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A 10" bbl?!
Over 550fps loss with that VVN 135 max load. Quite a loss.
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"I ain't got time to bleed!"
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pyro6999
Optics Retard OT TITAN Joined: December/22/2006 Location: North Dakota Status: Offline Points: 22034 |
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i imagine that you dont get complete burn in that short distance???
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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead" 343 we will never forget God Bless Chris Ledoux "good ride cowboy" |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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Not sure but guessing bbl length has more to do with it.
Once you go from 18" down the loss get kind of symetrical.
18" to 17"= 51fps
52
54
47
54
55
58
11" to 10" 63
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"I ain't got time to bleed!"
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Thanks for all the input guys. I've looked at the crown umteen times and can see no burrs or ilregularities.... Have tried 130, 150, 168Gr and am about to try 180gr partitions. The lighter bullets were amax and HPBTs. I have to think gunny did somein wrong somewhere. Son's afraid to take it back to same gunny. Wants to try recrowning himself!!!
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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OH BTW the stevens was stock so I believe it was 24" before. All the loads that weren't grouping were using Varget too. I was thinking of trying a fastwe powder but wnated to bounce things off you guys first. I think I'm gonna try and talk my son into returning it to gunny for eval...
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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SVT_Tactical
MODERATOR Chief Sackscratch Joined: December/17/2009 Location: NorthCackalacky Status: Offline Points: 31233 |
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Just be cautious of him wanting to start over. You only have .5" to work with.
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"Most folks are about as happy as they make their minds up to be" - Abraham Lincoln
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Yeah I know! Son uses this 308 for Deer and Bear. Bear hunting is on mountainside in thick laurel which is why he wanted shorter barrel.
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
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Bud, use short ammo...
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Opinion,untempered by fact,is ignorance.
There are some who do not fear death... for they are more afraid of not really living |
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jonoMT
Optics Master Extraordinaire Joined: November/13/2008 Location: Montana Status: Offline Points: 4853 |
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If the crown looks good (or at least before trying to tinker with it further) try some IMR 3031. Work it up stout as you can without over pressure signs. (All .308 loads I've ever shot well were on the high side). You may have to have him switch down to 165 or 170 gr. Partitions too. If you can get inside of 2 MOA, call it good for that barrel.
Now, consider for the future getting a custom barrel...and one done by a good smith. I was amazed at the velocities I got with my Rock Creek 24" vs. a Rem. 5R SS 24"...went from 2725 to 2795 fps. I'd bet that a comparable 16" barrel would still yield 25-30 more fps. That's not much, but they're almost always more accurate when smithed right and easier to clean too. In fact, I'm making that bet with my .308 AR build...going with a Rainier Arms Ultramatch barrel.
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Reaction time is a factor...
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