rifle is a rimfire conversion to 17 ackley hornet having problems going off. primers are well dented, but only about 15% go off the first time. another 10% will go off on the 2nd hit. firing pin protrusion is deep enough, spring has been replaced. entire interior has been polished, and nothing has made a difference. anybody have any ideas??

Is the fireingpin indent round or flat in the center? Could it be that the dia of the indent is not large enough?
Just throwing thoughts out there, tis a puzzler.

Assuming you have not got a faulty batch of primers it may be a chamber drilled too deep? Or, as it is a rimmed case, the groove is too deep?

I'd drop the block and then chamber a round and see how deep it seats against the top lip of the barrel.

quote:

Or, as it is a rimmed case, the groove is too deep?.

17 Ackley is center fire. I'd try a differnt lot# of primers before anything else! given your description.

the round is rimmed & the fit is right on. (kobe did the bbl work) primers are cci small rifle. i'm reluctant to go to pistol primers with the intensity of the round. the hit on the primer is round and smooth. i'm really bewildered, next thing is to try some other primers, pistol included and see if i can find some consistency

WAG:

Can the firing pin move forward before the sear is completely disengaged?

Take it back to Kobe and let him check the firing pin and the breech bolt hole. I have found brass in the breech bolt hole which would keep the firing pin from falling correctly. Check the strike of the pin on the primer. How close is it to the center of the primer. Check headspace on the rimmed case head with a feeler gage and a headspace gage, not a case gage.

I try to make the firing pin tip shaped like a Rem . 742 with a taper. This helps keep from breaking the pins. The point of firing pin is about .060 dia. and about the same amount of protrusion of .060 Was the action a converted 22LR to center fire? Check the bushing if a screw was used to reduce the dia. of the hole. I always welded up the hole and recut the bolt hole.

There is so many possible causes it will be hard to solve.

Just my 2ct's worth

This is my tools used for the Martini conversion. After welding up the #1 punch is used to start the process. The last piece of barrel is used to ream the bolt face square to the center line of the barrel.

les - this is a rimfire conversion. we bushed the hole and redrilled. i've flocked with the firing pin so much i can see it in my dreams,the hit is close enough to center and the breechblock etc. has all been cleaned and polished with the idea of having something hang up. this last time i welded up a new firingpin to lengthen the protrusion out to .080 with the idea of travel not being far enough. i just ordered another striker and spring from numrich to start from scratch with

Butch

I would shorten the firing pin up to .056-059. The Martini has a short fall and I have had to replace the firing pin spring with a strong heavier coil so the pressure was strong enough. A pin can be too long and with a short fall not get enough force to fire the primer off. I have seen this happen on Double barrel shotguns with too long a pin. Make sure that you have a round tip. I use the pointed end in #4 tool to line up the breech block to center fire by lowering the breech block by removing a small amount off the lever cam area until it fits.

Butch,
Get the protrusion back to .060" or a bit less like Les says. Then try switching to Rem. primers. CCI are the hardest in the industry.

Les, Could you describe what each of your tools in the picture do?

Thank you!

The first thing I do to a breech bolt is weld up the large firing pin hole. Next you need the #1 punch which has to be .003 smaller than the firing pin body. You use the punch to just nick the area inside the breech block. Tool #2 This will allow the center point drill to start a spot where the #55 drill can then go thru the breech bolt. Again the body has to be .003 smaller than the firing pin. Tool# 3 This is a small taper 1/2 reamer made with 0-1 drill rod. Turn the taper and then file away 1/2 diameter. This is an eye ball test in trying to get the D type reamer down to size. A set screw holds the reamer into the drill body. Reamer the breech hole slowly and check the depth of the reamer from the front end of the breech block. Don't ream too much from the hole. The tip should be about .058 in diameter to pass thru and bottom out with the forward end of the firing pin body. I try to make the tip end fit close to the taper which I reamed. This allows for a thicker firing pin from the body forward to the tip end. After I have the pin fit in place then use a stone to brake the sharp edge of the firing pin hole on the face of the breech block. This is just enough to keep the breech block from shearing primer when you extract when the block drops down. Tool #4 is used to line up the breech block with the center of the bore in the barrel. The small pointed end is used to fit into the breech hole thru the barrel short section. This is a piece of old barrel from a Martini which is reamed to .500 dia. The left end of this tool is a flat end mill cutter used to square up the breech block when you have the correct location on the small end tip into the hole in the block. I grind the cam part on the lever very slowly until the bolt is lowered into place. You need to use 0-1 drill rod and harden the tool and temper the cutter to light straw color. I have found that you have fewer firing pins brake off if you use my method. Don't snap the Martini action too many times are you will have a broken pin tip.

Use this information at your own risk as I don't know your ability doing this type of action conversion to a higher pressure cartridge than the original shell for the Martini actions.

I have milled a groove on top of the barrel to use as a base for the scope rings. This looks pretty good, but you must fit everything up correctly or go 1 turn around to line up all parts.

les - i did face off the breechblock in the bridgeport we drilled out the big firingpin hole in order to weld in a plug. firing pin is .062 diam.out of t-1. didn't do anything with the lever etc. i'm waiting for numrich parts if nothing else but to measure them. i just have the feeling that something is either slowing down the impact somehow.

got it - new spring, both the old one and the replacement i had were 3 coils short

quote:

Originally posted by butchloc:
got it - new spring, both the old one and the replacement i had were 3 coils short

So the new spring fixed the problem?

i believe it was 90% spring, but i replaced the firing pin also