Can headspace can affect accuracy?? Updates with pics.

Black Jack

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So I got this savage 10 fcpk (308) trying to zero to go moose hunting. First scope, (Bushnell Elite 6x24x40) no go, shoots half a mile to the left at 25yds and ran out of windage. Thinking something really wrong. Maybe the cheap 2 piece scope mounts. Replaced them with a one piece to see. Still shoots half a planet to the left. Ok, what about misaligned scope mount holes. To make sure 100% sure. Put in mill, indicate vise, clamp action and indicate base of scope mount. Everything is straight on. So scope mount holes are in line with action. Switch for scope #2 in stock (Bushnell AR223 3x12) Not shooting to the left and able to actually "zero" on paper at 25yds. Try at 100yds, rounds are everywhere. For all these test I was shooting reloads I had for my remington 700. Those were 168gr Hornady match. Next step, will try factory 308 ammo and Scope #3. Old Weaver fixed 6 power. Able to "zero" on 25yds paper. Try at 100yds and looks better. Shoots 4" right. Correction for 4" then shoots 4" to the left. ?? Maybe over correcting. Do not touch anything and just try to put two close together. Shoots right again and left again. So without adjusting for nothing the dang things shoots left and right with a spread of 8". So I stop everything and want to check this rifle a little bit more. I checked the headspace before taking it apart and found that the no go gauge was closing. Oh oh. We're taking it apart now. It's all stock so it's the smooth barrel nut. Man, they must of welded the dang thing and none of the "Savage" tools worked. I had to go hardcore. Now it's apart, removed the muzzle brake and the crown looks fine. Cleaned everything and will put it back together with the proper headspace. Now, with my limited knowledge of how accuracy works.

My question is it possible that headspace could be making this kind of variation from shot to shot?

So a few more things that was done before all this started. The rifle was cleaned. Scope base was torqued, removed reinstall. Every time i switched scopes they came with their own rings so they were loosen, re-adjusted, retorqued. Only thing left for me if the headspace doesn't help would be the ammo. I do not know what the factory ammo brand was. So this is going to be my new direction. Ammo fixing. Didn't know Will have to determine if ammo or headspace were doing this. After that I have no clue where to go. So let's see what can be done. Tks

UPDATE: So I took this rifle apart after finding out about the possible headspace problem. Reloaded 30 rds, installed the fixed 6 power scope and on the way for testing. Zeroed at 25 yds with 3 shots and was close enough for trying out 100yds. Shot twice at 100, touching, here we go, now we're talking. Readjust a little and fine tune to get to zero vertical. While trying to have a true zero, remembered I have a 20 moa base so I bottomed out at 4 inches or so above zero. All good, change targets and shot 5 rounds to see if it would still be together. Perfect, now it's staying together. So after all this what I changed was. I re-headspaced the gun and I didn't use the muzzle brake that comes with the rifle. Would have to try with the muzzle brake again to see if it throws my shots but right now it's shooting like it should I believe. Was able to group them inside 1/2" for 4 and then messed up the last shot and ended with a little under 1". Still 1000% better than when I started. :)

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So I got this savage 10 fcpk (308) trying to zero to go moose hunting. First scope, (Bushnell Elite 6x24x40) no go, shoots half a mile to the left at 25yds and ran out of windage. Thinking something really wrong. Maybe the cheap 2 piece scope mounts. Replaced them with a one piece to see. Still shoots half a planet to the left. Ok, what about misaligned scope mount holes. To make sure 100% sure. Put in mill, indicate vise, clamp action and indicate base of scope mount. Everything is straight on. So scope mount holes are in line with action. Switch for scope #2 in stock (Bushnell AR223 3x12) Not shooting to the left and able to actually "zero" on paper at 25yds. Try at 100yds, rounds are everywhere. For all these test I was shooting reloads I had for my remington 700. Those were 168gr Hornady match. Next step, will try factory 308 ammo and Scope #3. Old Weaver fixed 6 power. Able to "zero" on 25yds paper. Try at 100yds and looks better. Shoots 4" right. Correction for 4" then shoots 4" to the left. ?? Maybe over correcting. Do not touch anything and just try to put two close together. Shoots right again and left again. So without adjusting for nothing the dang things shoots left and right with a spread of 8". So I stop everything and want to check this rifle a little bit more. I checked the headspace before taking it apart and found that the no go gauge was closing. Oh oh. We're taking it apart now. It's all stock so it's the smooth barrel nut. Man, they must of welded the dang thing and none of the "Savage" tools worked. I had to go hardcore. Now it's apart, removed the muzzle brake and the crown looks fine. Cleaned everything and will put it back together with the proper headspace. Now, with my limited knowledge of how accuracy works.

My question is it possible that headspace could be making this kind of variation from shot to shot?

So a few more things that was done before all this started. The rifle was cleaned. Scope base was torqued, removed reinstall. Every time i switched scopes they came with their own rings so they were loosen, re-adjusted, retorqued. Only thing left for me if the headspace doesn't help would be the ammo. I do not know what the factory ammo brand was. So this is going to be my new direction. Ammo fixing. Didn't know Will have to determine if ammo or headspace were doing this. After that I have no clue where to go. So let's see what can be done. Tks

There was a batch of Savage 10 TRs a couple of years ago that would not get on paper - always shooting far left. I was a barrel issue. They got warranteed.
 
Consistent errors in the horizontal or vertical are usually a sign of a bad scope turret or sight mounting. As you tried different scopes I would check how your sight mounts. Just because the torque is right doesn't mean the mount is not moving and it takes only a few thou movement to give an error. I would be inclined to remove the mount fully clean with a good degreaser where it mounts make sure your mountscrews are not bottoming out.
 
Before pulling apart, any chance you measured how far the bullet was jumping?

If the jump was enough for your bullet to not be supported by the case mouth before touching the lands it could lead to accuracy problems, but your problem sounds mechanical.
 
Well - You just proved to yourself that either the rifle wasn't properly bedded before (eg action screws off-spec) or the muzzle brake is wonky. I'm not sure I understand your statement/concerns about headspace...
 
Well - You just proved to yourself that either the rifle wasn't properly bedded before (eg action screws off-spec) or the muzzle brake is wonky. I'm not sure I understand your statement/concerns about headspace...


I didn't modify or bedded the action. This time around I didn't even torque the action screws. Muzzle brake--> will put in lathe to see the runout. The headspace was too much. The action would close on a no-go gauge with reloads or factory ammo. That's the reason I took it apart and readjusted it. :)
 
I don't think the headspace correction would have an effect on accuracy, unless the barrel was loose or the recoil lug was mis-aligned before the correction.. Any irregularity the causes stress on the action will give grief. A good way to tell is how the action screws snug up - while tightening if they go from loose to tight abruptly, then things are good. If the screw gradually tightens over a turn or two, theres gonna be trouble.
Anyway, correcting the headspace is a good idea for other reasons. Let us know how the muzzle brake investigation turns out. Btw - it may not be the brake itself, rather the barrel threads not being concentric with the bore. A definitive way to check is to re-install the muzzle brake and shoot the same ammo you had success with...
 
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