Funny, I had a discussion about that very combination yesterday with a certain @JSH.Someone buys a throating reamer...the other buys a zero freebore chamber reamer? Hmmmm....Bwahahaha![]()
Have seen pressure problems with a jump to the lands on both. XX.X amount of powder and you start seeing pressure signs.Then same exact load of XX.X loaded with a "jam" into the lands and no pressure signs and, you can go up even higher on the powder with no ill effects.
I used the grizzly reamer with 0.100 freebore. Copy is here:
http://forum.accurateshooter.com/threads/my-new-22br.3981971/#post-37524506
This reamer works very nicely with the Redding 22BR FL dies. You could take this print and ask the reamer maker of your choice to make a zero freebore version for you. Another thing I would do is extend the OAL from 1.555 up to 1.565 so that you don't need to trim the 6BR brass as much after necking it down. The 0.253 neck is a no-turn neck on Lapua brass, with 0.003 - 0.0025 clearance.
0.100 freebore is really long for such light bullets. I'd go much shorter if that is your goal. You can see in my linked thread where I've posted pictures of various bullets seated to touching the lands in my gun.I too was thinking maybe .100 freebore, as I plan to shoo 53 and 55 grain v-max/BlitzKing bullets, and not the lighter 40 v-max. But maybe even then zero freebore would be best. not sure.
I wouldn't go 1.580" unless you don't mind scrubbing carbon out of the necks. It has been a while since I have sized some virgin brass, and I trimmed all of mine to fit my chamber, but I definitely didn't cut away 0.030" to get things to fit in my 1.555" chamber. Also consider that a 1.580 length and a 0.100 freebore is like a 0.125" freebore with a "normal" 1.555" chamber.My current 6br "Actual" chamber length, as cut on my barrel, is 1.579, and I love it, because my brass has never been trimmed and is 1.560-1.564 in length. Thinking maybe a 1.580 length will be good in this case, or may I just go a little shorter, see what I get, and trim once up front.
First, I would form the 22BR cases before I would spec the reamer and .100 freebore for those varmint bullets is definitely a big no! Depending upon the average case length I would determine the chamber length and freebore.I'm working on a 22BR no-neck-turn reamer right now. I had Dave Kiff build me up a 6BR no-neck turn, zero free bore, reamer back in 2005, but we can't find the data sheet, so I'm measuring and researching now, as I want them to match so I can use my same custom Harrel's dies.
I too was thinking maybe .100 freebore, as I plan to shoo 53 and 55 grain v-max/BlitzKing bullets, and not the lighter 40 v-max. But maybe even then zero freebore would be best. not sure.
My 800 pieces of Lapua 6BR brass measure .013 on the money, so I'm thinking .253 neck should be perfect. Does anybody know how much I can expect my necks to thicken, and lengthen, when going down to 22 Cal?
My current 6br "Actual" chamber length, as cut on my barrel, is 1.579, and I love it, because my brass has never been trimmed and is 1.560-1.564 in length. Thinking maybe a 1.580 length will be good in this case, or may I just go a little shorter, see what I get, and trim once up front.
Does anybody know how much I can expect my necks to thicken, and lengthen, when going down to 22 Cal?
Not to to be picky, but the 22BR is not a SAAMI cartridge.Next, why make the chamber length so excessive? If you went with your max case length plus .025, plus another .014-.016 at the transition into the lead, that’s another .040 of freebore, not to mention a chamber OAL of around 2.598.I had 22cal bushing, but it was for neck turned brass so it necked down too far (oversized), so there was massive neck tension when seating...and the FL bushing die wasn't quite able to reach/size all the way down to bottom of neck. Nevertheless, neck thickness went from .013 to nearly .014 according to my ball micrometer. But once seated with bullet, overall neck diameter was only .250 on the button. I think I'll just go with .253 neck and call it good.
Oh yeah, overall length of this piece of brass grew from 2.563 to 2.573. So I'll probably increase neck length by .020 or .025 over SAAMI, and then depending how how long chamber gets cut, I may or may not have to trim once up front. I might trim and anneal anyhow, since this brass has about 10 firings already.
Below is current 6BR with the 22BR in middle.
^^^^^ This! ^^^^^Not to to be picky, but the 22BR is not a SAAMI cartridge.Next, why make the chamber length so excessive? If you went with your max case length plus .025, plus another .014-.016 at the transition into the lead, that’s another .040 of freebore, not to mention a chamber OAL of around 2.598.
Is there a reason that you want so much extra neck length on your chamber in front of the brass? I use a borescope to verify the trim length where my brass is just a few thousandths short of the transition to minimize how much carbon can build up there.I had 22cal bushing, but it was for neck turned brass so it necked down too far (oversized), so there was massive neck tension when seating...and the FL bushing die wasn't quite able to reach/size all the way down to bottom of neck. Nevertheless, neck thickness went from .013 to nearly .014 according to my ball micrometer. But once seated with bullet, overall neck diameter was only .250 on the button. I think I'll just go with .253 neck and call it good.
Oh yeah, overall length of this piece of brass grew from 2.563 to 2.573. So I'll probably increase neck length by .020 or .025 over SAAMI, and then depending how how long chamber gets cut, I may or may not have to trim once up front. I might trim and anneal anyhow, since this brass has about 10 firings already.
Below is current 6BR with the 22BR in middle.