What is the ideal neck tension for AR10s and Semi .308s? I guess the question is what is considered too much? I've been using a redding bushing and usually get .003-.004...usually use .002 for my bolts...dont know if it maybe too much interms of accuracy....too looose=bullet setback and too tight=pressure spike or inconsistancy
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Neck tension and semis
- Thread starter CST
- Start date
Re: Neck tension and semis
0.003, although some can get away with 0.002
Anything more than 0.0035-ish and the brass will simply yeild and hold no tighter than 0.003.
0.003, although some can get away with 0.002
Anything more than 0.0035-ish and the brass will simply yeild and hold no tighter than 0.003.
Re: Neck tension and semis
Amen.
AFIC, no such thing as too much neck tension is possible w/handloads without adding sealant or Super Glue or tin-plated jackets (look up "cold solder"). The brass just stretches.
I've also never has a standard die set give too little for a semiauto, without added factors like a split neck (nothing can help that) or 1 batch of range pickup brass that was neck-turned real thin for a stupid-tight neck chamber.
Amen.
AFIC, no such thing as too much neck tension is possible w/handloads without adding sealant or Super Glue or tin-plated jackets (look up "cold solder"). The brass just stretches.
I've also never has a standard die set give too little for a semiauto, without added factors like a split neck (nothing can help that) or 1 batch of range pickup brass that was neck-turned real thin for a stupid-tight neck chamber.
Re: Neck tension and semis
I use a standard RCBS die, I haven't had any big problems. I might switch to a small base sizer die though.
I use a standard RCBS die, I haven't had any big problems. I might switch to a small base sizer die though.
Re: Neck tension and semis
"Anything more than 0.0035-ish and the brass will simply yeild and hold no tighter than 0.003."
Your idea is right but, actually, it's closer to .001". Prove it, measure a loaded neck, pull the bullet and measure again.
"Anything more than 0.0035-ish and the brass will simply yeild and hold no tighter than 0.003."
Your idea is right but, actually, it's closer to .001". Prove it, measure a loaded neck, pull the bullet and measure again.
Re: Neck tension and semis
I'm saying .001" under bullet diameter is all that matters. Aiming for .002" under is perhaps better for a practicle reason; to make sure you get enough to work with thinner than average necks.
Bullet "tension" comes from the springback of the brass and any smaller inside neck diameter is wasted from stretching the metal passed it's tension yield strength. Thus the ONLY thing a smaller neck ID accomplishes is to increase the seating effort and, usually, increases bullet run-out.
I'm saying .001" under bullet diameter is all that matters. Aiming for .002" under is perhaps better for a practicle reason; to make sure you get enough to work with thinner than average necks.
Bullet "tension" comes from the springback of the brass and any smaller inside neck diameter is wasted from stretching the metal passed it's tension yield strength. Thus the ONLY thing a smaller neck ID accomplishes is to increase the seating effort and, usually, increases bullet run-out.
Re: Neck tension and semis
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">so you guys are saying that .002 is the bare minimum for holding the bullet? or is that just too loose? </div></div>
We are saying it is application dependent. As in benchrest guys can "get away" with 0.000 in neck tension but generally stick to the 0.0005 to 0.001 range. Between 0.001 and 0.003 depends on the amount of abuse the cartrige encounters and needs to survive between the press and the final firing position. Semi-auto actions are part of the abuse side of the equation.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">so you guys are saying that .002 is the bare minimum for holding the bullet? or is that just too loose? </div></div>
We are saying it is application dependent. As in benchrest guys can "get away" with 0.000 in neck tension but generally stick to the 0.0005 to 0.001 range. Between 0.001 and 0.003 depends on the amount of abuse the cartrige encounters and needs to survive between the press and the final firing position. Semi-auto actions are part of the abuse side of the equation.
Re: Neck tension and semis
Make a dummy round and see for yourself what you are able to get away with. I sat and chambered and rechambered again and again to see what my minimums were. No setback for two or three chamberings, and I'm good to go.
Make a dummy round and see for yourself what you are able to get away with. I sat and chambered and rechambered again and again to see what my minimums were. No setback for two or three chamberings, and I'm good to go.
Re: Neck tension and semis
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">just seems .002 is alittle light for a heavy .308 semi...thats all. </div></div>
I agree with this, and recommend 0.003 for semis.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">just seems .002 is alittle light for a heavy .308 semi...thats all. </div></div>
I agree with this, and recommend 0.003 for semis.
Re: Neck tension and semis
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">theres got to be some accuracy concerns if the neck is too tight....fliers and verticle\horizontal stringing....
</div></div>
1. We're trying to explain that there's really no way to get a neck "too tight" from an ammo performance standpoint--arcane benchrest performance levels excepted. Plastic deformation of the brass metal to accommodate the bullet getting seated = no difference in "grip" after some level of undersize hole for the bullet is exceeded.
2. I have encountered more than one report (in isolation, no rigorous testing protocols used) of accuracy *increasing* in .30 calibers through use of tar-like neck sealant, increasing "bullet pull" or resistance to the bullet moving forward. Vertical spread decreased. More tension/resistance by itself is far less of a problem than *inconsistent* tension.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CST</div><div class="ubbcode-body">theres got to be some accuracy concerns if the neck is too tight....fliers and verticle\horizontal stringing....
</div></div>
1. We're trying to explain that there's really no way to get a neck "too tight" from an ammo performance standpoint--arcane benchrest performance levels excepted. Plastic deformation of the brass metal to accommodate the bullet getting seated = no difference in "grip" after some level of undersize hole for the bullet is exceeded.
2. I have encountered more than one report (in isolation, no rigorous testing protocols used) of accuracy *increasing* in .30 calibers through use of tar-like neck sealant, increasing "bullet pull" or resistance to the bullet moving forward. Vertical spread decreased. More tension/resistance by itself is far less of a problem than *inconsistent* tension.
