My buddy has a 7mm Mauser that we are trying to sight in for the season. He says it's never been cleaned to his recollection. So I soaked it overnite in Hoppes Bench Rest. I didnt want to use a brush on it just yet. Just would not come clean. It was then given to a gunny friend of ours and he said the bore was good but just needed a good brushing and 40 patches or so (he used the JB stuff).

Now, today I've found no improvement of groups at 100yds. Can barely keep it on ballistic paper. The scope mounts are tight. The scope is an old Bushnell Sportview fixed. I say replace the scope with something at least a little better and newer.

Is a new scope a good move at this point? (Especially since a gunsmith said the bore is good)


Thanx for your comments.



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That would be a logical assumption - the old Bushnell Sportviews were bottom of the line quality and anything else would be a big improvement.

The fault could still be with the rifle itself. Poor bedding, defective muzzle crown, loose bedding screws, fouled barrel, etc.

I'd start by disassembling the rifle and giving everything a good, thorough cleaning. Put it back together and check the barrel channel for clearance. Be sure to torque uo the action screws properly. Check the scope base screws for tightness. Ditto the scope ring screws.

Next trip to the range, carefully block up the rifle with sandbags, remove the bolt and bore sight at 25 yds, aligning the scope to center of target. Carefully fire 3-round groups to center the Point Of Impact (POI) exactly center on the target. Move the target out to 100 yds and adjust the POI to about 2" high above center of target.

If you still can't hold a reasonable group (1" - 2 1/2"), better have your gunsmith friend check out the muzzle crown and the scope mounts.

Be cheap. IF you've a gun with a scope (any scope that will fit that 7mm's mounts) that is KNOWN to be good, switch off the 7mm's scope for tht one even if the scope is totaly unsuited for the real use fo the gun. IF it's a 2X brtush gun scope or a 30X bench rest scope, if you knw the scope works right, better to test that before ordering a new scope in the heat of the moment.

IF the scope switch doesn't help, then you've not spent the $ on a scope, and can look elsewhere for the problem.
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all you'll lose is the sight in on the rifle with the know good scope...and that's just a good excuse to shoot it a bit to get it sighted back in.

Be cheap. IF you've a gun with a scope (any scope that will fit that 7mm's mounts) that is KNOWN to be good, switch off the 7mm's scope for tht one even if the scope is totaly unsuited for the real use fo the gun. IF it's a 2X brtush gun scope or a 30X bench rest scope, if you knw the scope works right, better to test that before ordering a new scope in the heat of the moment.

IF the scope switch doesn't help, then you've not spent the $ on a scope, and can look elsewhere for the problem.
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all you'll lose is the sight in on the rifle with the know good scope...and that's just a good excuse to shoot it a bit to get it sighted back in.





I just swapped out the scope off my pet 10-22 to see what's up. I think the crown is good or the gunny would have said. It's an old sporter with a floating barrel and bedded action. Just an old sweety we both have soft spot for.


Thanx, I'll tune in tomorrow after the barrel cools.


Perferator

Perferator
Do what kdub said and be sure the screws that hold the floor plate and the action are tight.

If it still won't shoot with a different scope try putting some shims, i.e. enough old credit cards under the front of the bbl between the stock and the bbl.

Lots of times accuracy can be improved with 5 to 7 pounds upward pressure on the bbl. Just loosen the floorplate screws, put in enough shims at the forward end of the stock so that there is good contact between the barrel and stock.

Tighten down the floor plate screws and shoot the rifle. There will either be a noticable improvement in accuracy or there is something else causing the problem.

If this does cure the problem you can make it permenant by glassbedding about two inches of the end of the forarm. Just rough up a couple of inches of the original bedding or bare stock, apply a release agent to the barrel, apply enough bedding to fill the area, clamp the stock in a vise upside down ( with suitable padding in the vice jaws so as not to damage the stock) and hang 5-7 pounds of weight on the end of the barrel. When set you will have 5-7 pounds of pressure exerted on the barrel by the stock. This would also be a good time to bed in the recoil lug. Bedding this in almost always improves accuracy

I have cured a lot of accuracy problems with military conversions with this system.

This may not be your problem, but used to be common with bolt action conversions.

Good luck running this down.

Thanx, for the pointers. We've basically run out of time with this piece. The scope helped some. The cleaning helped some. But for some odd reason this thing kinda does whatever it wants between 50 and 100yd. Short range is good but double it at 100 and the math just doesnt figure. The rounds are off the paper. My last shot of 20 more rounds was at the 50 and it was 1/2" to the right of bullseye. Dint dare shoot 100, agin.

Thanx again, guys. This will wait until spring.

Perferator

Most mausers have a fast twist, long throats and like long bullets. Are you shooting the 175 RN factory ammo?

Most mausers have a fast twist, long throats and like long bullets. Are you shooting the 175 RN factory ammo?



145gr......and that was the concern I had when it was the only available bullet.

Ok, here's what I think is yet wrong. I pushed about 20 or so patches thru it after doing the hoppes bench rest routine (initial wetting, scrubbing, dry patching...then soaking over nite). Then it shot about 10 rounds and given to our gunny friend. He said he used JB, brass brushed it and pushed 40 patches. So today after putting 20rds through it I thought I'd get my .270 boresnake soaked in hoppes and pull it thru about 8 or 9 times. Then I dry patched it....the first one looked like tar. The rifle was bought by this guys brother back in 75 at a high school deal. He never cleaned it. His brother doesnt remember cleaning it. Enter the "light" bullet situation and we have unstabilized flight characteristics. What ya'll think?

The receiver screws are so tight I cant even squeak 'em, they've been tight for decades....and the gun has shot well thru the years so it's not likely to be the cause. The crown is recessed and looking ok, visibly even though I can see where it's been gouged around the outer part of the barrel from hunting. The bore is nice but the grooves are still holding gum. The groove edges look distinctive but it's still dirty.


Patience, patience :D



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Perferator

Have you tried slugging the bore to verify groove diameter?