[fatboyclone]

my brother has a .22 semi-auto rifle that is (box) magazine fed. last week we were out on the range with a few different kinds of ammo ranging from the Winchester value pack to CCI Stingers. with a fully loaded mag of Stingers the little rifle went into burst mode. What could cause this type of malfunction? is it an easy fix?

[Oleg Volk]

Stuck firing pin?

[usp_fan]

The stinger is a pretty fast and high pressure round for the .22. It could be that the bolt is moving much faster to the rear then moving forward faster than usual. This could cause the hammer to either "bounce" off of the sear and follow the bolt setting off the next round, or could cause the hammer to move faster than the sear reset spring can, once again allowing the hammer to follow the bolt and set off the next round.

Try cleaning the trigger, sear, hammer and associated pins, springs, etc... Only lightly lube, as built up grease can slow the sear reset. If this doesn't work, I'd go back to regular ammo as a run away rifle isn't nearly as safe as it is fun.

--usp_fan

[mattd]

Inless the bolt or bolt stop is made out of rubber, stingers wouldn't have anything to do with it.

I'd clean the firing pin, wouldn't lube it, clean the trigger group also but only the slightest amount of teflon dry lube or clean it all out with lighter fluid, wipe it off let it dry and don't add any lube because the stuff left over from the lighter fluid is enough.

[hksw]

Which semiauto rifle?

[fatboyclone]

Which semiauto rifle?

not sure how much this matters, but its a Remington 597.

[hksw]

I know my way around a 10/22 pretty well and could have been more detailed for a diagnosis, but since it isn't a 10/22 not much help from me.

Knowing how a particular gun works in detail could be beneficial in determining what could be causing the problem and a more informative solution could be obtained, IMO.

[GooseGestapo]

You really didn't give enough information for a practical answer.
What Burst ?
The ammo/case
The barrel?
The action?
The magazine ?

The only thing that I can think of is that a case ruptured and vented gas into the magazine area and out of the ejection port.

After shooting a lot of what is known to be fairly "dirty" ammo, and not cleaning the gun...... And then firing the "Stingers" which though loaded to same nominal pressures as other .22lr, The case is longer and cartridge may not have been completely chambered and when fired, ruptured through the exposed case.
Also, as one other posted stated, it could have been a weak case ruptured at the firing pin impact location on the case rim.

I've had all of the above failures occur without any damage to the firearm.

Be sure to clean the bore/chamber on rimfires in spite of what some target shooters state. Chamber fouling with a rimfire occurs.

My S&W 617 requires the cylinder chambers be brushed ever 50 or so rounds or the cartridges wont chamber easily, and eventually wont chamber sufficiently to allow the cylinder to close.

Give more Info..............

[fatboyclone]

What Burst ? It was a 2-3 rd burst 3x in the same mag.

The ammo/case ammo was CCI Stingers... some Mini mags too but they didnt burst fire

The barrel? i dont know what you are looking for here the gun is a plain jane 597...no mods at all

The action? it is a semi auto

The magazine standard 10 round mag that came with the gun... also happened with a OEM mag that he had just picked up recently

i want to sell the rifle but dont feel comfortable doing that if it will malfunction. what should i do?

[Art Eatman]

I guess as a check, pull the bolt back and see if the firing pin protudes. It might be grungy, inside the bolt, and the pin might stick. Or, the Stingers might not be chambering all the way, and you're getting some sort of slam-fire situation.

You might hold the bolt back, and try chambering a Stinger by hand. Does it chamber all the way, without any particular effort? Or do you have to push it home?

All in all, do a thorough disassembly and cleaning. It's possible that the forward end of the chamber is grungy with some lead buildup. Use a copper bore brush and rotate it in that area to remove the lead (if any).

To test, load only two (or maybe three) Stingers. :)

Art