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View Full Version : Need advice on a 1:17 twist barrel



Jeffrey
07-06-2008, 09:09 AM
I'm considering purchasing a 1 in 17 twist barrel and would like some feedback on what velocity would work the best. I would like to shoot ammo in the 1040's. I have read a 1 in 17 is a warm weather barrel, 70 -80 degrees, but is there a preferred velocity for that temperature range.

Thanks

Colt.45
07-06-2008, 10:30 AM
Hi Jeffery
I have a Broughton 1-17" on my 40x,smithed by my friend Butch Hongisto.It does shoot much better in warmer weather than cold and although i believe this is true with all rimfires it seems more pronounced in the 17" twist.The ammo that shoots best for me is SK at 1080-1086 fps.Depending on your barrel you might have great luck with 1049 in hot weather but i think as it cools down you may need a bit more speed? I will buy a 1-16" next time as i think the 17" is too "picky".
Colt.45

Jeffrey
07-06-2008, 10:51 AM
Colt.45,
Thanks for the reply. I'm not locked into 1049 but after reading much from Mike Ross, Ross Precision, where it has been strongly suggested that the further you can move under the Mach I envelope the better the stability and performance could be and with 1040 possibly being the optimum.

Jeffrey

Brian Brandt
07-06-2008, 11:39 AM
Jeffery I shoot Eley match EPS at 1060 velocity out of my 1in17 twist Broughton and it shoots great. Also don't believe the velocity it has on the Eley box I had some 1049 last year when cronographed was up in the 1070's and my 1060 I am shooting this year is in the 1040's. Both lots of ammo shot really good out of my gun.

Colt.45
07-06-2008, 12:27 PM
40EZXS
My reply was based on testing,.....but it was lots of testing.It was also based on several matches last year and that is what i found with the 1-17" twist.And the velocity quoted was chronographed, not from a box or guessed at. Also i was in the top 100 out of 734 last year so although i'm not "a shooter who is procudcing winning Aggs" i did not fall off the turnip wagon yesterday. Brian is shooting very well this year and i wish him the best.
Colt.45

tim
07-06-2008, 01:48 PM
Colt.45,
Thanks for the reply. I'm not locked into 1049 but after reading much from Mike Ross, Ross Precision, where it has been strongly suggested that the further you can move under the Mach I envelope the better the stability and performance could be and with 1040 possibly being the optimum.

Jeffrey
I don't know who told you that but they're wrong Jeff. There is a lot more involved than that, as in tightness, bore taper, etc. If you are set on a given twist fine, once you get your barrel and get it fitted get yourself a few test lots of ammo from the 40's up into the 60's and see what it actually likes. The worst thing you can do is decide what you're going to shoot and then wonder why your new barrel won't shoot.

cpeters
07-07-2008, 12:02 PM
I'm with Tim on this one.

Charlie