Hot barrel?

[greyhunter]

Does barrel heat affect a muzzleloader as much as a centerfire rifle? Reason I ask is, my postal targets are the pits. The first shot may be good, but then the poi starts to spread, really spread. Thinking I may be shooting too fast in this hot weather? By the time I finish my ten shots, you'd think I had the shakes! Now if it's a trade secret you don't have to deevvulge, after all we are in a high stakes rifle competion here, but I think I will let the barrel cool off betweeen shots when I shoot my July targets. Opinions?

[Hank in WV]

I've had my barrels pretty hot on occasion, but They still seemed to shoot straight. A bigger problem for me is mirage.

[FlintSteel]

Check to see if your barrel lugs are elongated and not just round holes. You may be getting some binding and barrel distortion as the barrel heats up. Barrels expand when they get hot and the length can change. If you have tight holes in the lugs your barrel may be springing slightly changing the impact point.

[greyhunter]

It's a CVA Hawken, the first shot is really good, then it starts to wander. I'm going to try a few things, like wiping btw shots, letting barrel cool, and "shimming the barrel like Uncle Russ says, with pillow ticking btw barrel and stock. Russ says that will help a Hawken style group better. Aside from that, I lay a lot to my bad wrists which made me give up archery and now is jimmying up my aim. I may have to go to my Crockett that is a little lighter to shoot my postal targets. Any other ideas re hot barrel, let me know, thanks GH.

[Stormrider51]

The fact that you say the first shot (cold barrel) is on and the rest start to wander does sound like a heating problem.  If a barrel hasn't been properly heat treated it can certainly do what I call "snaking".  I once got in for repair a Chinese-made copy of the M1-A with a complaint of inaccuracy.  It would put the first shot in the center but the ones that followed were everywhere.  Once cooled completely, the rifle went back to center.  I tried everything I could think of starting with bedding the action and never corrected the problem.  

You didn't say, but are the shots stringing vertically?  If they are then wiping the bore between shots may cure the problem.  If it gets harder and harder to ram the next ball home then fouling is building up.  The build up changes the velocity of the balls and results in vertical stringing.  My hat's off to those who say they never wipe the bore between shots but I can't get away with it and retain accuracy.

Now that I'm getting older I have a problem that I never even considered before.  Successive shots make my arms tire more quickly than they used to and my offhand shooting isn't what it used to be.  If you haven't already done so, try shooting your Hawken from a bench using sandbags to eliminate as much of the "you factor" as possible.  If the rifle has the same problems on the bags then it is the rifle.  If the problem disappears it is you.

John

[greyhunter]

Thanks John, the first shot is dead on windage wise and 1+ high at 25 yds off hand. I didn't have a problem loading as I have a good patch lube. I only wiped the bore after 5/6 shots. The impact is not consistent, kinda like circling the bull, high, low,right, left, waugh. When I first got this barrel it seemed pretty accurate, maybe it is all me, will have to bench and sandbag it again to be sure, as it was good off the bags when I first got it.  

[Stormrider51]

Given that you say the rifle was good and then developed this problem, here's a couple more things to check.  

Examine the crown and the rifling just behind it.  A ding in the crown, even a small one, can throw off shots.  (I have a story about how I learned that a dinged crown can affect the accuracy of a previously accurate rifle.)  If you always use a rod with a centering device you can probably ignore this next one but look for uneven wear in the rifling just behind the crown.  The most critical part of any barrel is that last fraction of an inch that releases the projectile into free flight.  Uneven wear can cause the ball to spiral slightly as it spins.

Someone else mentioned this but check that the barrel wedges are tight and that the tenons they go through aren't stretched.  While you have the barrel out take a look at the barrel channel in the stock.  Wood can warp over time thanks to varying humidity and put uneven pressure on the barrel.  You may be able to see rub marks from the barrel on the wood.  If they are present lightly sand away the rub marks on the wood.  A coat or two of oil finish inside the barrel channel is good insurance.  Russ's idea about shimming is good.  If it solves the problem you might want to consider glass bedding just the tip of the forend.  It isn't traditional but it works and doesn't show.

Weigh the balls you have been using and throw any that are more than a few grains too light back into the pot for melting and recasting.  If the balls weigh, for instance, 300 grains and you find one that weighs 296, that light ball has either an air void or a pocket of impurities in it.  Depending on the size and location of the defect the ball will wobble as it spins.  BTW, swaged balls aren't immune to this problem.

That's all I can think of at the moment.  I apologize if I'm telling you things you already know.  I'm just going through the mental list I used in my shop over the years.

John

[greyhunter]

I'll sort the ammo, then try again, have shot this barrel about 150 some times at 70 grs fffg. It's a used barrel and I don't use a bore saver when cleaning, so muzzle wear is possible. Damn it's hot out here in the hills of Pa.! Will keep you posted.