Barrel-chamber misalignment?

[DanGuy48]

I read the article by Winker on this site but still wanted to ask about this. So, I'm an RSO at a local range, indoor, 25 yds. max. We are rated though for anything up to, and including, .50 BMG. A couple came in with a brand new Savage 112 in .338 LM, Vortex 4-12 (IIRC) to get it sighted in initially.

They used a bore site and aligned the crosshairs to the bore and fired at 12 yards. The shot was about 4 inches low and right. He inserted the borelight again, scope and laser still matched exactly. Fired again and same thing. I asked if I could take a shot. We inserted bore light and again cross hair and light seemed perfectly aligned. I ran the target out to 25 yards and fired. Low and right by about 6-7". At this point we decided something is definitely wrong.

They bought the rifle at Cabellas and did mention that the person there had the muzzle brake off fiddling with something for some reason. My initial suspicions are:

- muzzle brake is contacting bullet
- barrel crown is damaged
- barrel is not threaded true to action.

Winker also mentioned bent barrels but I really wouldn't expect that on this rifle. I told this couple I'd ask about this here to see if I am missing something, or if they need to send this one back. So, does anyone else have any ideas? Should the rifle be sent back? Am I just completely missing something simple?

 

[J E Custom]

I read the article by Winker on this site but still wanted to ask about this. So, I'm an RSO at a local range, indoor, 25 yds. max. We are rated though for anything up to, and including, .50 BMG. A couple came in with a brand new Savage 112 in .338 LM, Vortex 4-12 (IIRC) to get it sighted in initially.

They used a bore site and aligned the crosshairs to the bore and fired at 12 yards. The shot was about 4 inches low and right. He inserted the borelight again, scope and laser still matched exactly. Fired again and same thing. I asked if I could take a shot. We inserted bore light and again cross hair and light seemed perfectly aligned. I ran the target out to 25 yards and fired. Low and right by about 6-7". At this point we decided something is definitely wrong.

They bought the rifle at Cabellas and did mention that the person there had the muzzle brake off fiddling with something for some reason. My initial suspicions are:

- muzzle brake is contacting bullet
- barrel crown is damaged
- barrel is not threaded true to action.

Winker also mentioned bent barrels but I really wouldn't expect that on this rifle. I told this couple I'd ask about this here to see if I am missing something, or if they need to send this one back. So, does anyone else have any ideas? Should the rifle be sent back? Am I just completely missing something simple?

It is not uncommon for a rifle to shoot somewhere other than the bore siting indicates. bore siting is only for getting the zero "Close" final zeroing will be necessary without the bore scope.

Barrel harmonics, stock fit. bedding or lack of and ammunition used can all contribute to this.
If everything is tightened on the scope mounts and rings. adjust the recital to the bullet impact and then look at the group. if the brake is being struck by the bullet it should be apparent in the group size or you will see copper on/in the brake.

At 25 yards it will be hard to tell what is wrong. (The bullet strike should be low at 25 yards if a scope is used because of the difference in the barrel center line and the scope centerline.

J E CUSTOM

 

[DanGuy48]

Thanks for the quick and thoughtful reply. I heard back from them just a bit ago and they let me know that the rifle has a 20 MOA base on it. After hearing that, I suggested they check that the scope is returned to zero and shoot for best group. If it's still that low at 25 yards, it seems to me like the base might be mounted backwards. (?) Normally, if a rifle is sighted at 100 yards and it comes into our little 25 yard range, we do see them shoot low, but it's usually about 1 1/2" - 2". Thanks again.

PS. Nice brakes! I watched your video.

 

[LoneTraveler]

It is a Geometry fact that at close range, Like 12 yds. A rifle will shoot low, The distance between the scope center and the rifles bore center. If there is a lot of distance between Scope Center and Bore Center it will make it more. (See Through Scope mount). The shooting to the right sounds like something else is wrong. Maybe the muzzle brake. Check for bullet contact.
May have to take the rifle to a longer yardage range to prove what is happening.
Good Luck in finding and curing the problem.

 

[BULLBLASTER]

Can't the low and right be adjusted with the elevation and windage adjustments on the scope?

 

[ragsflh]

too close.need a least 100 yds on a 338.

 

[DanGuy48]

Just an update on this. I saw them again at the range and they said they took it to an outdoor range and could not get a good group at 100 yards. It belonged to the wife and, since she just had some major surgery, she decided to sell it and get a 6.5 Creedmore. Anyway, sounds like they just got a bad apple. He said they never did figure out the problem.