Helping a buddy work on hin Mauser 9.3 X 62. Here are the details on the rifle: Douglas barrel, timney trigger, action glassed, Walnut stock, barrel floated, Zeiss Duralyt 1.2x5.

From a cold barrel, this rifle shoots the Nosler 286 gr bullets under a dime. But as soon as the barrel get warm, the shots drop down about an inch and move about an inch and a half to the left.

Same result no matter who is shooting..

Anybody have any ideas?

Bedding, or a barrel that was not properly straightened. When hot, they tend to "walk" back to original dimensions.

Will this rifle be fired in bench rest matches, high volume prairie dog shoots, or prolonged volley fire in a battle? (Sorry Frank. Just couldn't resist being a smart @$$ ) Sounds plenty accurate for a medium bore big game hunting rifle used in just about any big game hunting situation. I'm assuming it has a sporter weight barrel, and not a stove pipe. Sporter weight barrels often do funny things when they get hot. Come to think of it, heavy contour barrels often do funny things too. It just takes them longer to get sufficiently hot to do so. Some, so called, stress relieved barrels might do better (Many, if not all, makers claim this is done in one way or another- from using heat after the barrel is made, to extreme cold before the bore is drilled). Perhaps your friend could have the barrel frozen by one of the companies that does this. Some say it does wonders. I wouldn't wast my money though. Sounds like that barrels shoots plenty good already. I'm guessing there are several A.R. members that would consider buying that barrel, if your friend decides to replace it.
Matt

What Matt says. I wouldn't care in the least as it puts the first couple into a dime size group then afterwards at the most 1.5 inches away.
Still way better than 99.9% hunters shooting game while in the field.
Heck, I would be happy if it shot 1.5 groups with a cold barrel at 100 yards.

So what kind of hunting would one do with a 9.3 that requires groups smaller than 2" at 100 yards in the field? And what animal is going to stand there waiting for the third and more shots?

If either of the first two shots is shot correctly, it is going to hit dead on point of aim with them anyway...

You needn't be unpleasant to him, but I'd sure be thinking while talking to him that this is a prime instance of making a mountain out of a mole-hill.

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I wouldn't care in the least as it puts the first couple into a dime size group then afterwards at the most 1.5 inches away

What did Shakespeare say? (I think it was the Bard) "Much ado about nothing"

I agree...not a rifle worth keeping. Put that puppy in a box and send it to me (FFL address to follow) cause I'm writing out $100 check as we speak.....

You do not have a problem.
Douglas does not straighten barrels.
Jon, enjoy your new rifle.

Pa.Frank

Sometimes a sporter weight barrel will group more consistantly with a little support near the fore end.

Next trip to the range take a handful of business cards and about 1.5 inches from the fore end slip enough cards between barrel and fore end channel to cause approximately 3 lbs of upward pressure on the barrel. You can now shoot some groups to see if your barrel responds to a little support near the end of the fore end. You can also vary the pressure by increasing/decreasing layers of cards.

If your rifle responds favorably to this treatment (a lot of them do) you can make the modification permanant by glass bedding a little strip at that location.

I also suggest checking the glass bedding job by placing a bore sighter in the barrel and alternately tightening and loosening the action screws while watching through the scope. Or set up a dial indicator between barrel and fore end. If there is any movement observed then your bedding is not done correctly. Also check for glass touching the action screws. Check for clearance at the rear of the tang and check for stock contact with the bolt. On a 98 mauser it is also easy to get too much tension the rear screw and bend the tang.

quote:

Originally posted by Pa.Frank:
Helping a buddy work on hin Mauser 9.3 X 62. Here are the details on the rifle: Douglas barrel, timney trigger, action glassed, Walnut stock, barrel floated, Zeiss Duralyt 1.2x5.

From a cold barrel, this rifle shoots the Nosler 286 gr bullets under a dime. But as soon as the barrel get warm, the shots drop down about an inch and move about an inch and a half to the left.

Same result no matter who is shooting..

Anybody have any ideas?

OK - "action glassed" and "barrel floated"

Frank,
Run dollar bill down under barrel 1st when cold and 2nd when hot. See if there is any resistance either hot or cold.

I think I would zero that rifle so that the aim point was centered between the hot and cold groups and go hunting. If I'm reading right, that would put him within 3/4" of the aiming point. I think that big .366" bullet should be able to make up for that minor aiming error out past 300yds.

I always judge my hunting rifles by how they group when firing four shots as quickly as I can accurately aim, as I might have to in the field if, Heaven forbid, I was to miss with the first shot. Most of them are good until the fifth shot and then start wandering a little but never enough to miss the vitals.

As far as fixing it, if the bedding is right about all I can think of is cryo-ing the barrel, which should not hurt but very well may not help.

I had a 6mmR about 40 years ago that was the same way. First two shots in a 1/2" or less, normally less and then low and right 1 1/4". After it moved it would stay there and print a 1-1 1/4" 10 shot group until it cooled off again. I killed more groundhogs with that rifle than any I've ever owned. I can count on one hand in 4 years of hunting avidly that I ever got or needed more than two shots. A national record holding benchrest shooter that was an accuracy smith on the side looked at it for me and said that he thought the factory (Remington) had straightened the barrel. I finally shot that barrel out and traded it off. It was a sporter weight barrel. It was so accurate for the first two shots that I couldn't re-barrel.

What are you shooting that requires more than one or two 286 gr Partitions to stop it??

Again, this is not my rifle, it belongs to an anal retentive friend that has an obsession with accuracy, no matter the caliber.. If he cannot get a rifle to consistently group within 1.5", he simply won't hunt with it.

Thanks for all the replies, at least now we have a few things to check..
and thanks to Craftsman, we were thinking the same thing about possibly adding a pressure point.

Ok, if he really wants to pursue it; I had two Shilens about 15 years ago in 338 RUM that did exactly the same thing; I sent them back and they lapped them and re-stress relieved them; problem solved. Douglas does not lap barrels and I don't think that did anything; they had residual stress, somehow. I think the heat treatment killed the stress.
Another true story; a friend has a .308 shilen that did the same as yours; he is a machinist; he said that the stress could be relieved by smacking the barrel with a brass hammer (out of the stock and hanging). I will be damned if it didn't work.
Another thing; make sure you aren't cleaning the barrel too much (yes you can), and the shot movement is not the result of going from a clean bore to a fouled one.

Where exactly did he smack it, and how hard? What kind of brass hammer?

I have a candidate for this....

Heating for stress relieving starts at about 700 F to 1200 F .Above that other things happen.
Cryogenic cooling has been suspect for me as there are too many scams about that.1200F will certainly remove all the stresses. A dollar bill is a bit thin for testing free floating .A thicker business card is better.
In any case there are lots of things that introduce stresses .Back in gunsmithing days they taught that full receiver bedding + 2" of barrel was the best .Worked for me.

quote:

Originally posted by Pa.Frank:
Again, this is not my rifle, it belongs to an anal retentive friend that has an obsession with accuracy, no matter the caliber.. If he cannot get a rifle to consistently group within 1.5", he simply won't hunt with it.

That is his problem not ours. I tend to have less and less sympathy for his type anymore.

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Originally posted by Chuck Nelson:

quote:

Originally posted by Pa.Frank:
Again, this is not my rifle, it belongs to an anal retentive friend that has an obsession with accuracy, no matter the caliber.. If he cannot get a rifle to consistently group within 1.5", he simply won't hunt with it.

That is his problem not ours. I tend to have less and less sympathy for his type anymore.

(A lot of winning benchrest shooters have rifles which perform the same way, including three national champions I know personally.

He smacked it quite hard about 1/3 of the way from the receiver, 3 times.
Or, as stated by mete, have it heated by a good heat treat shop; tell them you want to stress relieve 4140 and they will know what to do. This is not a home project as you will get bore scaling if you try to do it in an oxygen environment.
I also have no patience for those who won't accept a perfectly good hunting rifle but the OP seems nice enough.....
However, when I meet rifle owners like that in person, I tell him to get a life.

Gary Anderson, the only person to win consecutive gold medals in Olympic 300 meter free rifle competition, once commented that he didn't believe that his rifle was capable of minute of angle performance. Rather than concentrating on perfecting his rifle, he concentrated on perfecting his shooting, spending hours dry firing and mastering his trigger control.

Having the finest and most accurate rifle in the world and the most lethal ammunition means nothing, if the shooter is unable to place his shot where it belongs. Technology is no substitute for skill, and skill in target shooting or hunting cannot be mastered at the loading bench and the bench rest.

Right on.

I once knew a fellow who advertised that he would stress relieve barrels for $100. You sent him the barrel and 100 $1 dollar bills. He'd take it and the money to a local topless bar and pour a couple cold ones thru the bore. He guaranteed that stress would be relieved. Not necessarily the barrel stress.

I know Douglass heat treats at least twice while manufacturing their blanks. Who turned the finished barrel?

I'd say try the fore end pressure point unless the owner is planning on using a bipod.

If my rifle puts 2 first shots on each other and the rest are an inch and a half I'm not worried, at most you have 2 calm shots at an animal and more likely one. If shots one and two don't get him you are not missing him on shots 3, 4, and 5 because the rifles inaccurate.
If it were my rifle I'd probably try a little fore end pressure and call it good and go hunt that thing.

Thanks for all the suggestions, here is what we are going to try.... We are going to put a long screw or bolt through the front sling swivel hole with a small pad to gently add pressure to the barrel and adjust as necessary see if that corrects the problem. And if it does, glass in a permanent pad.

Sound workable?

Thanks!

quote:

Originally posted by Pa.Frank:
.....

Thanks for all the replies, at least now we have a few things to check..
and thanks to Craftsman, we were thinking the same thing about possibly adding a pressure point.

Yeah, That's where I was going, too, with the dollar bill checks.

Think if you could find a point where the barrel binds either hot/cold it would help barrel with the placement of a pressure point.

PS: I've used aluminum duct tape to experiment with adding a pressure point. You can change the size and placement of the tape w/o doing anything permanent till you find the right spot.

quote:

Thanks for all the suggestions, here is what we are going to try.... We are going to put a long screw or bolt through the front sling swivel hole with a small pad to gently add pressure to the barrel and adjust as necessary see if that corrects the problem. And if it does, glass in a permanent pad.

Sound workable?

Be sure that the pad is V shaped so the barrel will return to the same position. Also go easy with screw pressure, they can exert way too much pressure if you are not careful.

If you have not already done the screw, I would suggest that you stop before it is too late.

The screw will create a lot of variables and you will NEVER get a permanent solution unless you Loktite the screw. The risks of increasing your frustrations are very high!

I would suggest that you just use plastic swipe card pieces. If it improves the group, just stick it with Super glue & you are done.

I have read of people using business cards to get the barrel pressure or even just a few blobs of hot glue under the barrel.

You need to be careful not to use too thick a piece. All you need is just enough pressure to prevent the barrel from moving around without too much upward pressure.

At an inch and a half, you really don't have a problem IMO..However, you might tweak it a bit. I would suggest you try putting some upward pressure on the forend to stabilize the barrel. a shim or two as a rule works on some rifles..NOT ALL BARRELS SHOOT BEST FREE FLOATED, contrary to some beliefs. Some even shoot best bedded tight all the way, more common in the bigger bores but starting with the 338 and 9.3x62 it seems to me.

What's warm? Will it group two or three before it shifts? In reality, you'll never need more than that at any appreciable range. Any additional shots will be so close that that kind of difference won't matter. And, by that time, the barrel will have cooled. JMHO