How deep to chamber a .22 rimfire?
Is it is important for accuracy that the bullet be engraved by the rifling when a the round is chambered?
If so, how far should the bullet be engraving? On center fire chambers most people think the amount of jam is important. Is the same true of .22 rimfire?
Most reamers are .600. A few of the newer ones are coming out at .560. I've seen good shooting barrels both ways.
I want to say that ive read somewhere the smiths say they headspace to like .043-.047. And the rim thickness std on a reamer is .043, so i dont know if they are reaming till the gauge protrudes .043 for rim thickness or if they are adding another 50 thou for contact with the rifling. Im sure someone could clarify, anyways, bump. Id like to know also since i will be chamber my first rimfire barrel shortly.
I'm about to try to do my first one as well. My reamer should be here in a week or so. I'm sure there are a lot of guys that know the answer but it must be classified information.
Headspace is not my problem. I know how to set that and I also know it only has to be close, .042 to .046 works well and there is no difference in how the gun shoots in that range.
The problem I'm having is I've checked some chambers and found the best shooting ones all engrave the bullet when a round is fully inserted in the chamber and exstracted. Others barrels I have do not engrave the bullet and they don't shoot as well. Is this always the case? If so, how much jam should one try to achieve when chambering???? Perhaps this is determined by the reamer itself, If so I'm thinking some reamers must produce better shooters than others!
Someone out there must know. The question is: will they share?
Where's Kathy when you need him?
There's a lot of different chamber reamers, and a lot of different bore sizes, and a LOT of different opinions on which reamer is best. Lot's of different reamers work for a lot of different people. Folks just don't want to get into an arguement. I imagine that's why you aren't getting an answer, and there's some truth that a lot of it is classified too. I'm of the opinion that reamer size depends on the bore size in the grooves as Mr. Calfee has written about. If you'll do a search on this forum on chamber reamers you should turn up some info.
Truth is you'll get a lot of different answers if folks chipped in and answered your question, and they may all be different and all correct?
I like my chamber to barely start to engrave the front drive band on an Eley EPS bullet, and I mean barely. I want the diameter to allow cases to slide in easily so it doesn't rub the lube off the bullets. Fat ammo very rarely shoots well. If it's case mouth size at the leade compresses the lube and forces in in front of the drive band that's good too. I don't want the engraving to cut through the front drive band to the nose of the bullet. Too much engraving doesn't seem to work well on tight bored barrels. Two degree leade angles will not engrave the bullet as much and the old 5 degree leade angle, because the angle isn't as steep. Just my opinion on what I've seen work. Could be totally wrong? This is on BR rifles that'll shoot groups in the .0's and .1's if everything's right(meaning not "all day long").
Mr. Bill Calfee has wrote articles on this I do believe, and they're good ones to go by.
Last edited by Kent Owens; 06-09-2008 at 11:36 PM.
IIRC, .040 to .055 is the range of bullet driving band engraving Iíve heard mentioned the most in old posts. Into or touching the second driving band normally. But the throat angle and land height play a role in the actual depth, probably because of the effort required to close the bolt with a steep throat angle reamer.
My drop-in tight bore lilja (eley #5 reamer?) engraves a wolf-mt a full tenth of an inch, and a GM barrel on my 10/22 doesnít engrave at all but just touches the driving band on wolf mt, so there are some exceptions. The GM shots far better than it has a right to, so just touching must not be an outright group killer.
IIRC again, B.C. said in an old post he sometimes pulls the barrel several times while building a rifle, altering the amount of engraving until the chamber works best with the ammo he intends to use. He manually extracts the rounds while testing and cuts the extractor slots after the chamber is working.
Hope this gives you a place to start while searching, but its best to not trust my memory as the final word!
I was typing while you were posting Kent.
Thanks for your post, good information and the just touching part helps explain the results Iíve seen with my last barrel.
I admit I have experimented with this a bit. Last year I ahd a .217/.2215 barrel that used a .2250 straight chamber reamer with a 2 degree leade on.
I had the chamber cut and polished out to allow a distance of .1280 from the back of the case head to the breechface. That allowed it to engrave about half way back on the second drive band of an Eley EPS bullet. The rifle shot in the mid .2's and done well. Deepening the chamber to allow it to just barely engrave the front drive band brought groups sizes down 1/10th" and that's a lot! I went a step farther and deepened it to where the lands were just barely making marks in the bullet lube and not cutting the lead bullet, accuracy remained the same. No better, no worse.
I think a chamber well done is as important as the reamer, within reason.
In rimfire BR we have to have a rifle capable of sustaining a minimum of 50 shots and maintain top accuracy. A good chamber will allow that to be done without fouling and throwing shots here and there. Again, just an opinion.
Other folks know a lot more on this subject than I do.
Last edited by Kent Owens; 06-10-2008 at 12:48 AM.
Guys thanks for the responses.
I think you guys set me on the right track. When my reamer arrives I'm going to chamber .100 swallow and see how it works. Then keep going deeper until accuracy degrades. At worst I'll have to cut the barrel shoulder and take a little off the cone on the breech. I'm taking the easy way out, no exstractor slots to cut.
I ran the search and looked on BC's web site but didn't find much. I do understand nearly everything written on forums like this are only opinions, and what works for one person may or may not work for another but this is so basic I would have thought there would be more hard info on this subject.
The centerfire guys openly discuss bullet jam and many use this to determine when the barrel has eroded enough to require the barrel to be set back.
If anyone knows where the Calfee articles are on this subject please post the location. I tried reading though a few of the threads that touch on this subject but they were so full of riddles they were of no use. I never found the bottom line if there was one.
Good shooting guys!
What chamber reamer size are you using and what is the size of your bore in the grooves?
If you can find my article "The good, the bad and the ugly, of rimfire chambers, read it.....
What you are planning to do probably will not tell you what you wish to know............
Real quick, you can't ream a chamber, without finishing it, then test it and come to any conclusive results.......an un-finished chamber will not reflect the true accuracy of your barrel's potential...........
Keith, this is why all "serious" rimfire benchrest gunsmiths completely finish their chambers........
Find and read the article.......
Your friend, Bill Calfee
Kent and Kathy (Bill)
I ordered the reamer from Dave Kiff. I told him I was using a tight bore Lilja, 4 groove, and would be shooting Eley Match EPS ammo. He seemed to know what I would need. I think he is sending me what he called the " Eley match reamer" and a .214 pilot button.
I will look for your article. Now I have the title maybe I can find it. I am curious as to what you are calling a "finished" chamber.
Thanks for the help!
I found the article, it is in the February 2006 issue of PS. Thank you for the article and thank you for sharing this hard learned information. It was exactly what I needed.
Did you follow up with an article on how you finish your chambers, if so, could you give me the title of the article??
Thanks again for sharing. You are a man among men!!