Re: ATTN: sr90 velocity loss with 2" shorter barrel
Now I've got a few posts to catch up on.
first is sr90,
I've had a couple of amazing groups at 100yds while testing my 338 yes. But they don't come everyday. I've had 2 (5) shot groups in the .1's with it using H1000 powder. The smallest measured .183". I'll see if I can get a picute uploaded of that group. Something odd about .338 caliber bullet holes producing groups in the .1's in paper. It just doesn't look right. I have a sizable handfull of groups in the .2's and groups in the .3's are pretty easy to produce. It's a very long story but I'm still fighting with it at 1000yds. I've fired some damn scary 8 and 9 shots groups (boy isn't that always the same ol' story right?). But my smallest official 10 shot group in competition is only 7.7". That's not that great compared to todays BR standards. But when it comes to score shooting with it... it's great. Hell the last match in NC last year I shot a 21" group (that sucks because I as trying something different), but still shot a 90 score. Almost won for score with the largest group of the day!! I've had more than one 9 shot group in the 4-5" range only to have 1 go out. But in competition anything less than 10 shots is wishful thinking.. bottom line.
I've had some things changed this year for different harmonics on the barrel so we'll see. Not many guys are using 338's in the BR game right now, so I'm trending into somewhat unknown ground. The 338's just don't have the tight grouping ability of the hot 30's and 6.5's right now. But I guess I still have some of that stubborn ol' German in me, and I will make this 338 shoot. I'm still tuning this new barrel up, but so far I think I see good progress. Will be at the 1000yd range on Monday testing as a week today is our first match of the year. Hopefully I can get it tuned up pretty good on Monday if good conditions are available. If not I'm just pi#$ing in the wind. Already I've had 5 shot strings with R25 powder with single digit min/max variations over the chrono. It never did that before and the groups are more round than up/down. Yea haa. Vertical flyers was what was killing me before. We'll see.
you can't get off that easy. It's going to cost you a beer or 12!!
The case you are refering to is called the 6mm Vais. But the 6mm Vais does have a "improved" shoulder and not simply the Swede case necked down. There's also a 22 caliber (22 Vais) version of it that a friend of mine up in Virginia uses. He get's 3600fps with Bergers 80gr bullets. But just last year he started loosing bullets in flight and had to back off. Those thinned jacketed Bergers will come apart much easier than other match bullets. But the accuracy at that speed was amazing.
I personally don't have any first hand knowledge/experience with the 6mm version though. Your right it is very similar to the 6mm Ackely and that has had very good success in a couple 1000yd LG rifles with the heavy bullets.
But a few general comments: I don't see how you could go wrong with that case though. You essentially end up with a 6mm Ackley using tough Lapua brass that measures absolutely great! It has to work as good if not better. The other added benifit is the large internal capacity of the Lapua brand of the 6.5x55 casings. I think you would be surprised if you water volumed the Lapua Swede case (necked down) compared to a domestic brand of 6mm Rem brass. For instance look at the outside case dimensions of the standard 6.5x55 case compared to a 6.5-284 case. Yes I've had the Ackley shoulder added to the Swede case, but even with that you still wouldn't think the internal volume would be that far off. But it is. I've got the same internal case capcity as the 6.5-284 Norma brass that is currently being produced right now. I get the same velocity (3000fps w/140gr bullet) the 6.5-284 shooters are getting and using approx 3gr less powder to boot with better and MUCH TOUGHER brass than the Norma stuff. But the Norma brass does measure as good if not better than the Lapua in my expereince. But it isn't as tough and has less internal capacity.
I think that answers all the questions at this point. If I missed something, smack me in the head. I'll wake up and try again.
[ 02-16-2002: Message edited by: Steve Shelp ]