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Discussion Starter #1
I do not own a centerfire bolt action but a friend has this problem. Browning A-Bolt in 7mm mag and 300Mag. Both doing the same thing. Bolts are sticking. He has tried Federal and Rem ammo in 150 gr bullets. Both A-bolts are stainless. He took the 7mm to a bench shooter who was suggested by a local gun shop to be a good gunsmith. He did a good cleaning on the gun and even test fired it with no problems. He went to the range Friday and both of his guns are doing the same thing. He sent his Federal ammo to company and they sent him some more ammo but there is nothing wrong with it I guess because it does it on Remington ammo also. I know sticking bolts are an indication of overpressure. He says there is more than normal discoloration around the head of the spent cartridge. I suggested that he do a very good chamber cleaning and inspection. He says he sees nothing like dents or scuffs on the brass. Anybody got any ideas or heard of this specific to magnums or Abolts or Brownings or something?
 

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Hi, Chief:
  I'm wondering if he's letting his ammo cook in the sun before he shoots?  He's likely doing something different if the gunsmith didn't have any problems. :confused:

Bye
Jack
 

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Discussion Starter #4
He says he has not let his ammo get hot. I know it sounds like a headspace problem but on two guns at the same time? Are bothe the 7MM and 300 true belted rounds or are the belts for show? This guy has to take a gun to canada this fall and he can't trust either of these to perform in the field until he gets it fixed. He has to report his serial # in August to the outfitter. Any more ideas?
 

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Chief,

If it hasn't been done yet:

I would get right on the horn to Browning and see if you can talk to someone from the technical department. Explain the whole situation and if need be return the rifles to them with the ammo that is giving you the trouble.

I wouldn't be surprised to hear that this is some dimensional problem with these two guns that occurred on the manufacturing line.

FWIW,

Ray
 

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Hi, Chief:
  I know this is farfetched, but is he confusing cocking force with a stiff load? Most centrefire rifles cock on opening, so the force needed to lift the bolt handle is considerably higher if the gun has been fired than if it hasn't been fired. It's the same with a lever action. Let the hammer down, cycle the action, then cycle the action again while leaving the hammer cocked. See how easier it is?

  Tell him to hold the trigger back while he closes the bolt on an empty chamber, then release the trigger and note how hard it is to lift the bolt. Then he should fire a round and note any difference in the required force.  I haven't handled an A Bolt for a while, but some bolt actions are pretty stiff on the cocking motion.

  The point is, two different calibres, two brands of ammo and the gunsmith OKed it. :confused:

  Another thing. A dirty bolt face will give you a dirty case head after you pull the trigger.

Bye
Jack
 

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Discussion Starter #7
OK guys. This friend is running out of time. He did a lot of cleaning and things improved for a round or two and then the problem returned. It is not bad as it was. He can get it open with pressure but it is still there. We are thinking that something is still dirty. I have told him to take a brush and put it on a drill and work on the forward part of the chamber. We have discussed cleaning before and both of us are realizing that we have not been doing a great job. He is going to use some bore paste on a patch and spin the brush. He is using an ammonia base cleaner now and getting copper out for the first time. He will send them back to Browning after the Canada hunt but for now he has to get one working or take one of his old Rem. in a caliber that will be questionable or borrow someones rifle which he probably sill not do. He is also cleaning the bolt and getting good results there. I just wonder if there is an ejection function that takes place when you raise the bolt that is not happening. Can he soak the whole bolt assembly in solvent and scrub with nylon brush? Wow ,I really am in the dark.
 

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This may be a longshot but, make sure that there is NO oil left in the chamber.....that will definitely have an effect .Remember the 22 Jet?
 

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The Smith revolvers that were chambered for the 22 jet use to blow up alot thus causing Smith to stop production in that particular chambering.It wasnt really the guns fault,something about oil in the cylinder with a bottle necked cartridge caused a problem with pressure.When it was fired it would not have room to expand properly which would force the cariridge back HARD! OR if you were lucky it would just seize into the cylinder. Again,not the weapons fault,but it did pose a liability problem.Im sure someone else here could give a much more technical explanation.
 

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A correction and explanation is needed here. The .22 Jet Mag that Smith & Wesson made was a design failure of the cartridge case. There were no blown up guns that ever can back to the factory. Many Jet owners "acquired" .22 rinfire cylinders and converted to the straight side wall wildcats. The problem was that the Jet cartridge with its very tapered sidewalls had to have absolute dry chambers. If not the fired cases would seat back and lock up the handgun! No matter how much instructions were give to the owners, if was ignored...so the pistol was taken off the market. Sad, but True
Best Regards, James
 

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Discussion Starter #12
Sorry I am so late letting you guys know. My friend got the problem to stop when he did a thourough cleaning og the chamber with Sweets. He used a wire brush on a drill after cleaning and oiling with Kruel. Then he cleaned again with the Sweets. Whatever had built up in the chamber around the neck or neck down area was the problem. Since it had happened at the same time in both his guns the only common factor was a new bottle of Hoppes #9 copper solvent. Could be a bad lot or a formula change or something else but he won't use it anymore. He has gone to Butch for his regular cleaning.

Thanks for the help.
 

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This is only a guess, but is there any chance, that after getting the rifle back from the smith he took it home, cleanded, oiled it up real nice, and then the next time out to shoot did not remove all the oil from the chamber area?  If he has left oil in the chamber, then upon firing the brass cannot expand and grasp the chamber walls like it is supposed to do.  This lack of grasping will increas backthrust and give indications of overpressure, such as sticking bolts.  Have he do a really good job of removing all oil from the chamber and bolt face before shooting.
 

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Discussion Starter #14
I believe we got it guys. Thanks so much. I talked with him Sat. and he has turned in his Rem to the outfitter for his trip to Canada. Both rifles are working fine but he chose the old reliable for his trip.

Some time before he had this problem I was talking to him about cleaning and he indicated that he always ended cleaning by putting a coat of oil on the barrel. I told him that removing that oil was something that was always suggested before firing. He said it would just burn off. Now we all know what can happen if all oil is not removed before firing. I suspect he had a pretty good build up of oil related sludge in that area of the chamber and it took some serious cleaning to remove.

He won't be doing that anymore.

Thanks for the help.
 

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A buddy of mine has two A-bolts that have exhibited the same problem, one a .300 Win Mag, one a .338 Win Mag.  He tracked both problems to brass being too long.  This doesn't make sense in your case, since you are using factory ammo, but maybe Browning cuts their throats short, and your buddy got an extra short one (low end of the tolerance).  Maybe you could make a chamber cast.  Or, try trimming .050" from some brass, reload to a "factory level" and give it a try.

Tom
 
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