Self doubt abounds

TexasSS

Trouble with a scope mounted on a sage ebr m1a. The scope is a Vortex Viper 4-16X44 (No experience with this brand),with a sage M14DCSB (sight base made for the chassis). Accuracy is all over the place as in on and off paper, and before I go to accusing the tools to being junk I want to make sure I'm not screwed up, which is probably more likely. The scope rings should be tightened to approx. 15 inch lbs right? And any thoughts on this optic/rifle/chassis combo?

charliemeyer007

I use lock tight on the base screws.

Is the rifle new or well broke in already? What ammo are using? Is your bore free of copper fouling?

4" at 100 yards off a rest is the most I would tolerate, less than an inch would make me happy.

added I bet your rifle doesn't have the twist rate to properly stabilize a 175 gr. Try some 150 gr. It takes about 100 rounds to iron in a bore. I like Shooter's Choice for removing copper fouling. A pull threw cleaning system or perhaps some sort of crown protector for use with a regular rod.

Allow the rifle to cool between groups - bolt open works better.

TexasSS

rifle was made in the 90's but kept unfired until I bought it last year, so not broke in. The ammo was Federal Premium .308 175 gr which use in both my Remington 700 and LRT-SASS AR-10 with very good results. As far as copper fouling or any other barrel issues I can see no obvious flaws with a bore light but that is the best I can do.

TANK78Z

If You mounted the sight base and rings and they are both correctly attached and tightened , I would look at the crowning of the muzzle, if it looks and feels good, I would check for proper fitment of the barreled action to the stock, if good I would then try a couple other weights of bullet and even another brand of ammo. the Vortex should not be the problem, but if you have another scope you could mount it to help eliminate the vortex and or the mounting system from the equation.

101AIRBORNE

Have someone else fire the rifle.

ChrisStreett

I recently had to work in a new SA M1A. On it I mounted a Burris XTR 6X24 with Burris rings set up on an ARMS18 mount. For the life of me I couldn't get it where it needed to be. I ended up having to shim the mount .013 because the outside of the reciever was just a "hair" out of spec.(A cast obviously. Qualty control has definitely suffered over the years.) This made all the difference in the world. From what little I know on the subject (I certainly don't have anywhere near the expertise of those who have responded.), you will be very well served to consider some of the suggestions of the resident experts. They'll get you on track.

beantownshootah

I can't comment on your equipment, though it sounds to me like something is probably askew.

But on your psychology ("self doubt"), one question. Are you able to shoot *ANY* rifle accurately (ie to less than two minutes of angle?).

If you can't, then give this problem rifle to someone you know is a good shooter to try grouping it for you. If they also have a problem then you know its the gun and not you.

But assuming you are a proven competent shot with OTHER rifles, and the trigger on this gun is reasonable, I don't see any reason why you should be shooting all over the place. Again, this is probably the gun, but you'll have to work it from ground up to find out.

TriumphGuy

An often forgotten bit of craftsmanship is to mount the scope with the reticle near the middle of its adjustment range. Getting it close can involve anything from simple shimming to machining bases and rings. If you don't get it near mid point the adjustments become non-linear and unstable in recoil. Most modern sporting rifles and scopes can be bolted together without worrying too much about this, but your combination of rifle/scope/mount might add up to a scope being right on the edge of its adjustment with springs right at the end of their travel to hold the internal reticle tube stable.

dcs shooters

try a lighter bullet [;)] My M1A NM doesn't like 175's either [^]