Pinned firing pin

sevendozen · #1 03-18-2019, 03:19 PM

Has anyone put a pin over the firing pin and seen a reduction in accuracy?

jam_ppp · #2 03-18-2019, 03:34 PM

My understanding is that it's less an accuracy thing vs. "flyer" thing.
Meaning, having the FP pinned should reduce flyers, but not necessarily tighten up the rest of your shot group.

'ol shooter · #3 03-18-2019, 06:40 PM

Pinning the firing pin is done to make the firing pin strike consistent.
Normally the bottom of the cocking handle that rides in the top of the bolt holds the firing pin down, but that allows more or less vertical movement depending on how good the fit is.
The pin stops any vertical movement, and that along with shaping the firing pin tip so the energy of the strike isn't wasted on the outer rim where there is no priming compound.
This pic is not a 10-22 pin but you will get the idea of a properly shaped pin strike on the right:

This pics shows where the priming compound is and why hitting the outer rim spends strike energy in the wrong place:

I have several 10-22's, all but a few I built up from parts selected by me, and all have had the bolts re-worked by Que, among the improvements are pinning the bolt above the firing pin.
Hope you find this useful.

Chaser · #4 03-18-2019, 07:40 PM

Fewer flyers because that pinned FP hits the same place every stroke.. no bounce = consistent ignition.

Try one... home brew... .10 split/spring roll pin.

sevendozen · #5 03-18-2019, 08:32 PM

Wellp....I'm stumped. I've been shooting .686" groups at 50 yards with this rifle all winter. CCI SV then CCI Blazer. Stock parts. I have not changed anything except pinning the pin. For 40 or so rounds Saturday, I shot an average of .536" with CCI Blazer (no fliers) at 50 yards. Then it started opening up. Like...1.5" and up. I checked all my nuts, bolts, torques, cleaned the rifle, changed ammo back to Standard Velocity, and it didn't get any better. I could spot nothing out of the ordinary.

I put it back together, went out this morning, and shot the same 1.5 and up groups. Played with takedown screw torque with no real results.

Starting to think it's my scope.

Chaser · #6 03-18-2019, 11:29 PM

Quote:

Originally Posted by sevendozen

Wellp....I'm stumped. I've been shooting .686" groups at 50 yards with this rifle all winter. CCI SV then CCI Blazer. Stock parts. I have not changed anything except pinning the pin. For 40 or so rounds Saturday, I shot an average of .536" with CCI Blazer (no fliers) at 50 yards. Then it started opening up. Like...1.5" and up. I checked all my nuts, bolts, torques, cleaned the rifle, changed ammo back to Standard Velocity, and it didn't get any better. I could spot nothing out of the ordinary.

I put it back together, went out this morning, and shot the same 1.5 and up groups. Played with takedown screw torque with no real results.

Starting to think it's my scope.

Check the crown and make sure ya have not dinged the end of the barrel.. then CLEAN it. Scrub the chamber with Hoppes#9 and a bent bore brush.. then run 5 or 6 passes with a BoreSnake and Hoppes.
Sounds like severe fouling.

'ol shooter · #7 03-19-2019, 01:25 AM

Recheck the vee block screws too to assure that the barrel is in tight.

Chaser · #8 03-19-2019, 11:04 AM

What scope are you running...? AO on it? Rimfire optic or a Hunting Rifle optic? 1" error is a ton at 50 yds.. but parallax may be your issue... BUT, clean.. squeeky CLEAN it...pick away at the variables.

Roadrat · #9 03-19-2019, 12:24 PM

What size "split/spring roll pin" do you use?

bubba68 · #10 03-19-2019, 02:03 PM

Quote:

Originally Posted by Chaser

Fewer flyers because that pinned FP hits the same place every stroke.. no bounce = consistent ignition.

Try one... home brew... .10 split/spring roll pin.

Do you use anything other than the spring tension to hold the roll pin in place in the bolt?

Chaser · #11 03-19-2019, 02:12 PM

Quote:

Originally Posted by Roadrat

What size "split/spring roll pin" do you use?

Hi RR!
.10 OD x.32ish - I think I buy the .75's long and cut in half and grind/file to .32 - just measure/mark/eye ball that fore gap and trim as needed to fill the gap.. Now, the .10 pins are NOT all the same.. the ones that worked the best and are slightly larger/tighter I got from Ace Hardware.. on the ones I had that were slightly undersized I tapped them on a punch (1/16") to spread them a tad..then worked them off with a ViseGrip.. don't break your punch tip off.. keep it all straight or it will snap... I broke one a few years back.

Once ya get the right size pin debur the ends and then it should lay on top of the gap without sliding into the gap.. then drive it into the gap.. once lined up one good firm whack with small hammer get's it started..then use a punch to lightly tap into place which should be approx. .01 above the FP.. need ever so slight clearance..don't go too far and contact the FP.. it's a SonnyBeach getting it back up. A 1/16" punch taps into the pin to hold it and spread it a tad... comes in handy if you want to use that method to hold it in place for the first whack. Obviously most of these functions need a bench vise... pad the jaws with something so it doesn't mar the sides of your bolt.. I use the magnetic/plastic jaw protectors.

Chaser · #12 03-19-2019, 02:14 PM

Quote:

Originally Posted by bubba68

Do you use anything other than the spring tension to hold the roll pin in place in the bolt?

Nope... and I have done approx. 20 this way.. all have stayed in place thru thousands of rounds.. the main thing is getting that pin in TIGHT..

I take my dial-gauge when I go to buy pins.. .10 in most cases works well.. I had one bolt that for whatever reason needed a .11.. so I spread that pin .. oh and orient the pin so the slot faces UP.

bubba68 · #13 03-19-2019, 05:36 PM

Quote:

Originally Posted by Chaser

Nope... and I have done approx. 20 this way.. all have stayed in place thru thousands of rounds.. the main thing is getting that pin in TIGHT..

I take my dial-gauge when I go to buy pins.. .10 in most cases works well.. I had one bolt that for whatever reason needed a .11.. so I spread that pin .. oh and orient the pin so the slot faces UP.

Well I decided to go for it and pin the firing pin on my bolt this afternoon. Everything went ok I must have a bolt with a slightly wider slot as a .1 pin would go in the slot without any pressure. I cut a short piece off of the roll pin and spread it out a little but it still did not fit as tight as I thought it should. So for my piece of mind I mixed up a little JB Weld and put a tiny spot on top of the pin just as a little insurance for it to stay in place.

Probably will be a while before I get it to an outdoor range to see how it works. Not to far from a 25 yard indoor range but no way to rest the gun on the bench and I don't do well enough off hand to really see if the pinned firing pin helped any.

Roadrat · #14 03-19-2019, 05:50 PM

Sorry, being ignorant I read this as 10 split/spring roll pin and had no idea what the "10" was for. I missed the POINT in front of the "10"

Try one... home brew... .10 split/spring roll pin.

Thanks

Chaser · #15 03-19-2019, 06:05 PM

Quote:

Originally Posted by bubba68

Well I decided to go for it and pin the firing pin on my bolt this afternoon. Everything went ok I must have a bolt with a slightly wider slot as a .1 pin would go in the slot without any pressure. I cut a short piece off of the roll pin and spread it out a little but it still did not fit as tight as I thought it should. So for my piece of mind I mixed up a little JB Weld and put a tiny spot on top of the pin just as a little insurance for it to stay in place.

Yupp.. I tell ya almost nothing about these 10/tweekie2's is identical.. almost/sorta/kinda is a pain.. that's why I mentioned spreading the pin.. and the JB Weld is a nice touch

Another method I remember using to spread the pin is clamping it in ViceGrips or the Bench Vise to give it a tad OVAL shape.. bingo.