Just a question about 22rf's. In a earlier subject it was mentioned something about shooters now using slower twist 2 groove or "was it shallow grove"?
In order to get ammo at slower speeds to preform !! Or did I get the wrong idea from what I was reading.

ThnxTim!
I was talking to Bob Collins about different lots of Eley and he asked what I was using it in and when i mentioned a BSA Martini he said that I probably needed higher speed ammo for that type of rifling in order to upset the base band properly. Then mentioned something about slower and I thought he said 2 groove rifling..... Like a old timer I thought about it later and wondered about the 2 groove thing!! are they in fact using shallower or less rifling in order to have the slower ammo upset to fill properly or did I miss understand him? 
Tom

I cannot recall what twist rate my Lilja barrel is, but I shoot it extensively at 200 ysd with Eley EPS 1064 fps ammunition.  It does spectacularly well.  I can measure the twist rate if anyone cares, but the bottom line is that I called Lilja and asked for their recommendation and I took it and ran.  The barrel was more or less their standard Chro-Moly benchrest barrel of the time (about 3-4 yrs ago).  It will shoot low 240s for average and commonly into the mid and upper 240s with regularlity every day that the weather is even half decent.   

If I felt I needed more stability at 200 yds, I'd go with Eley EPS ammo another 100 fps faster.   

Brent

I'm curious about opinions on twist rate for 200yds/meters, also keeping in mind I sometimes shoot in pretty windy conditions.   
I shoot .22 BPCR silhouette matches; 50 - 200 meters. I've been using Lapua Master & Signum. 
I've had a gun barrelled with a Douglas 1-14 and seems to do a bit better in the wind than my other 1-16 barrels.

rimfire, my chamber is a Lee Shaver chamber.  I can't tell you more than that.  It is definitely a match chamber, but I cannot tell you more.   

Brent

.22Hepburn wrote on Mar 13^th, 2008 at 8:33pm:


That may ultimately be because it is a better barrel over all. It has become a more popular belief among BR shooters amd barrel makers that over all faster twists are more wind sensitive.

Tim_s, the comment about faster twists being more wind sensitive is curious since in the cf long range realm the trend is toward faster twists with a goal of more stablility. The trend seems to be toward 38 & 40 cal rifles with 10 and 12 twist barrels. Or could be that this is really not a good comparison.

Brent, you missed the important part. Firstly this is 50yds. where all .22 score type sanctioned matches are held, well yds. and mtrs. There is no formal score BR shooting done at 100 that I know of. Many 250's are shot at that distance. None, however, have scored 25 x's. These were club matches, but club matches where some of the countries best BR shooters turned out and duley witnessed. The x on these targets is 1/16" and the current word record, I believe, is 23x.
  As to the referenced chambers, it is perhaps one of the true "black arts" of the best of the match .22 game and there's lots and lots of secrets out there.
  Unfortunately, Chester passed away recently and with him a lifetime of invaluable information . We are truley diminished.

Sorry about the curve ball, it was referenced with an IR 50 target in mind. That's my frame of reference regarding .22's

I believe the faster twists in the centerfire are for heavier bullets. You need the faster rate to stabilize them at our velocities.

40-82Hepburn - I don't have any way to post them but if you will PM me your snail mail address I will make copies of both Eley and Lilja chambering reamer specs and mail them to you - you have a good day now - the rimfire - cdpersons

Rimfire, I believe you may have misinterpreted something. Bill, Chet and others do in fact believe the throat has to be lapped in, or burnished, as Bill calls it, but it has less to do with sensitivity than consistancy.
 Among the advocates of it, it is believed that it helps the base upset properly and seal well, it helps reduce the buildup of accuracy robbing lead-carbon ring building in the leade, as well as aiding that initial wax distribution.
 It is my personal belief that the reduction of that ring of fouling might be the most critical.
 Lots of the non-cleaners don't realize that once that hard ring builds, every slug that passes through it gets swaged down and will not seal as well, robbing accuracy in so many good barrels. We are only talking, maybe, a couple tenths but remember we have come to understand in rimfire match barrels, a bit of taper in the bore is desirable, but if you swage that slug past that hard ring of fouling, guess what, you have no more taper.