doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Sticky opening gun

Have you tried each barrel seperately. That can narrow the problem by 50%.
Appears to be firing pin drag which can be caused by overly long FP protrusion in some cases and by a hard edge on the firing pin at the edge of the radius. Sometimes you just need to break that edge of the transition from the major diameter of the pin to the radiuius and that may cure it. I would not shorten the pins, thats a last resort.

Have you tried each barrel seperately. That can narrow the problem by 50%.
Appears to be firing pin drag which can be caused by overly long FP protrusion in some cases and by a hard edge on the firing pin at the edge of the radius. Sometimes you just need to break that edge of the transition from the major diameter of the pin to the radiuius and that may cure it. I would not shorten the pins, thats a last resort.

I believe that it is a combination of issues, Firing pin protrusion and shape, and head space. Head space is probly a bigger contributor to your problem. Find shells with a thicker rim and check results.

I agree with 2-P on all points. Funny how often that happens. Maybe because he's usually right in his answers? The primers are protruding because the rim cut is too deep. The rough chambers add to this problem by allowing the shell walls to grip the chamber walls so the pressure pushes the primers back. The primers then wrap around the too long and too pointed firing pins. The primers also protrude into the FP bushing spanner holes, causing more drag. Like 2-P suggested, the first things I would do is shorten the firing pins to protrude about .045" at most and round them nicely. Then do what is necessary to make the cocking levers or rods start to cock the hammers slightly sooner. The too-deep rim cuts could be made shallower by cutting them deeper and installing rings of steel permanently. This might cost more than the gun is worth. Maybe Mike Orlen does this. If so, he will be less expensive then most. If you just bought the gun chances are the seller had new pins installed and they were not properly rounded and fit for length.
Two more points: the problem is not that the primers are not being seated deep enough. The primers are backing out when the shells are fired. Proof of this is that the battery cup is flush with the rest of the head.
Other poing: remove the firing pins to round and shorten them. Trying to "stone them in place" will make a mess out of the standing breech face and never do a good job. You may have to make a spanner to remove the fp bushings but do this the right way, with the pins out of the gun.

Looking at the picture of the shells in the chamber it is hard to tell but looks like shell heads are higher than barrel face at bottom and fit correct at top. Shell rim cuts might have been done at an angle to cause this . If this is the case get rims cut slighty deeper at bottom.

The rim cut is cut with part of the chamber reamer. It goes round and round, in line with the bore. The only way the cut would be deeper at top than bottom or vice-versa is if the breech end of the barrels was not square with the bore. In any case, the cut is too deep now. Cutting it deeper would make that part of the problem worse.

If the pins are penetrating so deep that they are dragging primer metal with them after firing and scratching the breech face on the way up, as seen in the first two pics, then that is certainly where I would start. They do look awfully pointy.

Pile of issues there.
Looking at them all, including the pointy pins --
-the chambers look to have been 'touched up'
-the striker discs don't meet their 'timing marks'
-headspace if FUBAR

I wonder if those pins are replacements that someone put in there to deal with inconsistent ignition -- which could have been brought on by the 'chamber work' that someone had done (screwed up)... the chamber work being what caused the headspace issue...

Can't tell all from the photos and story, here's to thinking on it.



--Tinker

I re-suggest my previous post. You are not going to be removing a ton of metal off the end of the pins, so, take a small stone to the field and stone a little off the ends of the fp's and see what effect it has. This is too easy to do not to try. If you are worried about scratching the bolt face, then use a little masking tape over the bolt face and push down where the pins hit, to force them through the tape, and do your rounding, then remove the tape before you fire.

binko

Yesterday I wanted to shoot a few shells with Fiocchi primers to see if the results were the same. In the Fiocchi hulls are 616 primers and in the Winchester HS hulls are 615 primers. I am still getting dimples with a point but they don't look like the Winchester 209s did and the gun opened without any effort at all. The indentation in the primer on the far left actually looks shallow.




I pulled the pins to measure them and they are .446" (L) and .458(R), maintaining the difference that I got when measuring how much each protruded from the breech face.