Shorty M14 issue

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I know that some HPBT .308 bullets have been known to group tighter at 2 than at 100 yards due to stabilization BUT from 8moa to 1 moa is baffling.
Time for me to confer with my mentors and see if this condition has been encountered before.
 
8MOA @ 100 meters cannot turn into 1 MOA @ 300meters unless the projectile has it's own propulsion and guidance system. Anything resembling rifle accuracy at distance is unachievable after such a poor start. The vector's have already been set, no matter when the round finally stabilizes, if it ever does.

I've read of No4Mk1T's shooting ever so slightly less MOA at 600yds than at 300yds ( 1.25 versus 1.5 etc) because of the the unique N04 action dynamic's, left hand twist ,fast twist rate etc etc, but 8MOA at 100 and then 1MOA at 300, I just can't logically understand how???????

8 MOA from a rifle, would make me look for keyholing at 100 from an unstabilized bullet not put to sleep because of too slow a twist, or not engaging rifling hardly at all, and if the round became point on stabilized at 200 meter's, I can't see the groups finding their way back to POA after the buckshot start.

If there is a dynamic at play here,.... I'm missing it, and I'm all ear's.

There has to be a variable change from the 100 to the 200 target????
 
OK, here is a picture.

Handloads, 43gr. of RL15 powder, pushing a 150gr. Hornady HPBT,

I used the same target. I first put it out to 300 and shot five rounds. They're marked "1". Then I brought it back to 200 and shot five more. They're marked "2". I pulled the left one a little but otherwise they're almost identical. I was aiming at the red dot.

Then I brought it to 100 and I was aiming at the black, smaller dot I made with a marker. They're marked "3". They spread out like crazy.

To give you an idea, the middle blue strip is 2 inches wide.

scaled.php
 
I did that. Same results. It's not the scope. Is it possible that because of the shorter barrel the bullet doesn't fully stabilize until it's past 100 yrds? I'm thinking it might be keyholing when it hits 100 ?

I don't know...it's just an idea.
I find that a bit hard to believe friend. Only because I own an 18.5 inch barrelled .308 M1 Tanker copy & I do not have these kinds of issues presently.
 
Try different bullet's. Also what was the powder that was used? Also try with off the shelf ammo and compare the 100 meter resualts if it still groups like this post back.
 
I know this may sound silly but what if there are other unknown variables at play here?

Maybe you just need to find a better handload for your rifle?

Perhaps bullets at minimum diameter & a worn rifle barrel. How is the crown? What kind of muzzlebrake/flash-hider are you running? I say this only because the US Army match M14s had specially reamed flash suppressors. Come to think of it, once I had wandering group issue with my VAR barrelled M1 rifle in 30-06. Turns out the after market flash hider shot loose, which I was unaware of, & this was playing havoc with my groups @100 yards. Thankfully I caught it before any damage was done.

just putting these questions out there.......



Good luck to you!
 
I would have said the scope's parallax adjustment is all screwd up at 100, but if it still shoots like that with irons then it's a different story.
 
I will go out on limb here and suggest you re-zero your rifle and scope at 200m it really looks like the issue is not the rifle but an issue of scope mount it appears that your rifle is shooting high from where your POA as you stated . When a rifle is zeroed at 100m and shot from 200m the difference is 2" vertical difference between rounds fired at 100m and those fired at 200m
 
My Norinco M14, cut and accurized by the M14 Doctor, shoots around 8MOA at 100 yards and close to 1MOA at 200 and 300 yards with hand loads.

Any possible explanation?

Huh?, this is not possible.
A bullet wandering 8moa off center at 100 yards cannot miraculously suck itself back towards center at 200/300/whatever yards. The path has been set.

Edited to add:
Guess I should read the whole thread before yapping.
OK, you shot at 300 first, then 200, then 100 and that’s when things started going awry.

This isn’t an ammunition issue, your scope or mount has failed/loosened up after your 200 yard shots would be the first thing I would suspect.
 
Huh?, this is not possible.
A bullet wandering 8moa off center at 100 yards cannot miraculously suck itself back towards center at 200/300/whatever yards. The path has been set.

Edited to add:
Guess I should read the whole thread before yapping.
OK, you shot at 300 first, then 200, then 100 and that’s when things started going awry.

This isn’t an ammunition issue, your scope or mount has failed/loosened up after your 200 yard shots would be the first thing I would suspect.

No, scope is solidly mounted to the mount and the mount is solidly screwed to the receiver and locktied. I wouldn't be able to keep getting tight groups at 200 and 300 if the scope was loose.

At the end of the day this isn't a big deal. What it shots at 100 yrds is good enough and what it shoots beyond is even better. I am just really curious what the mechanics of it are.
 
Oh, you’ve shot the rifle more and it consistently does this.
Then I would consider what Gun Lover posted, the scope’s parallax at a 100 may be causing you this issue, which is also a little odd because generally scope manufactures set the parallax at 100 or 200.

I would drop a different scope on the rifle and shoot it again, if similar sort of issues occur then I would remove the mount and shoot it with irons to see what happens. It just seems to me that scope/mount is the most logical culprit.
 
When aiming lower at the 100yard target is it possible that your bullets a strikeing snow, twigs, grass/ weeds? on the way to the target. then when you aim higher for the longer distance the bullets clear the obsticles? I'v seen it happen!
 
I shoot it from the bench, with no chance of it hitting anything before the target. And I've tried iron sights with similar results. Except that my groups are not as tight further out because I can't see as well as I can with a scope, to aim small at a far.
 
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