Rimfire headspace

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silver 55

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In the March edition of Rifle magazine there is a good article on rimfire headspace. I hadn't thought about it much in the past so I took a piece of angle iron, drilled it with a #1 drill and got a .228 hole near one edge. A few minutes with a saw and a file and with the addition of a dial indicator I now have something to measure the rim thickness.
Okay, where do I go from here. The ammunition my 10/22 likes measures around .041/.042. The stuff it doesn't like is .035/.036.
Should I find how much headspace my rifle has and if it is much more than .043, should I find a way to close up the tolerances

Has anybody looked into this?
 
You could rework your bolt to a .043 headspace. Fair warning though if you get to tight the bolt closing on the round can cause it to fire.
You could buy a quality after market Bolt. Dlask and Kidd come to mind. I run a Kidd and a Rimfire technologies bolts in different rifles.(RT does not do Bolts any more)
There is also a couple people on Rimfire central that rework bolts, you could have them do it.

I reworked a Magnum Research 10/22 Magnum bolt to a proper headspace, I used a lapping stone with some 800 grit sand paper on it and carefully took down the bolt face checking frequently with a depth Micrometer. You have to keep the bolt perfectly square to the lapping block or you'll mess it up real fast.
 
Innercity said:
You could rework your bolt to a .043 headspace. Fair warning though if you get to tight the bolt closing on the round can cause it to fire.
You could buy a quality after market Bolt. Dlask and Kidd come to mind. I run a Kidd and a Rimfire technologies bolts in different rifles.(RT does not do Bolts any more)
There is also a couple people on Rimfire central that rework bolts, you could have them do it.

I reworked a Magnum Research 10/22 Magnum bolt to a proper headspace, I used a lapping stone with some 800 grit sand paper on it and carefully took down the bolt face checking frequently with a depth Micrometer. You have to keep the bolt perfectly square to the lapping block or you'll mess it up real fast.
Click to expand...

Thanks for your reply. I have a small lathe so I was thinking of taking down the headspace in it. The question I have is...was it worth it? Did you get a noticeable reduction in group size?
 
The reason i took down the headspace on that 22 magnum was that I was getting light strikes on all types of ammo. The pocket on the bolt was way outside SAAMI specs for a .22 Mag chamber.
As for accuracy the gun had no noticeable change except that it went bang every time. 22 mag is a hunting round not for super accuracy.

remember .043 is the Min for rim space by SAAMI specs

http://www.saami.org/specifications...SI-SAAMI-Z299_1-Rimfire-Approved8-31-2015.pdf
 
It's a 10-22... just use the ammo that shoots best in it... it will never shoot as well as a bolt...
 
guntech said:
It's a 10-22... just use the ammo that shoots best in it... it will never shoot as well as a bolt...
Click to expand...

Yeah, you are right, it is only a 10/22. But at 50 yards, out of 5 shots, I can cover 3 of them with a dime. The other two aren't far away. I just had a bit of a hope that the group could tighten up with some work. Oh well, guess I will have to keep at it.
 
silver 55 said:
In the March edition of Rifle magazine there is a good article on rimfire headspace. I hadn't thought about it much in the past so I took a piece of angle iron, drilled it with a #1 drill and got a .228 hole near one edge. A few minutes with a saw and a file and with the addition of a dial indicator I now have something to measure the rim thickness.
Okay, where do I go from here. The ammunition my 10/22 likes measures around .041/.042. The stuff it doesn't like is .035/.036.
Should I find how much headspace my rifle has and if it is much more than .043, should I find a way to close up the tolerances

Has anybody looked into this?
Click to expand...

Would you post a picture of your headspace gauge? I can't totally visualize how you made it and I would like to make one.
 
Sounds to me like drill a hole in metal just large enough for the cartridge to drop in but be held up by the rim. Zero calipers to metal thickness then place over rim, voila! Rim thickness gauge.
 
RabidM4U5 said:
Sounds to me like drill a hole in metal just large enough for the cartridge to drop in but be held up by the rim. Zero calipers to metal thickness then place over rim, voila! Rim thickness gauge.
Click to expand...

No, he says he's got a dial caliper mounted somehow which is what I would like to see. Though I guess I could just use a magnetic base to stick the dial gauge to the length of angle iron but I would still like to see silver 55's if he would show it to us. I'd like to build something quick and easy to use.
 
I have a a RIA 10/22 clone and I milled my bolt face down to .043" to square up the boltface and correct the headspacing ( confirmed with depth mic, not this caliper nonsense lol). The difference is noticeable.
 
elimsprint said:
No, he says he's got a dial caliper mounted somehow which is what I would like to see. Though I guess I could just use a magnetic base to stick the dial gauge to the length of angle iron but I would still like to see silver 55's if he would show it to us. I'd like to build something quick and easy to use.
Click to expand...

Sorry guys, I am a dinosaur, don't know how to post photos. I drilled the initial hole about 1/4 inch from the edge and used a saw and a file to open up a channel from the hole to the edge. My dial indicater is mounted on a magnet base, I set it up at first with the plunger beside the hole. I used the adjustment wheel to bring the indicater to zero. Moved the base over so the indicater is over the hole and turned on the magnet. I can lift the plunger with my right hand and slide a rimfire case into position with my left.
 
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