ernierod1 Posted August 20, 2007 Share Posted August 20, 2007 Am considering building a 9mm BE target pistol on a 1911 platform. I have choice of 1:16 twist or 1:32 twist. If I am going to be using bullet weights in the range of 115 to 125 gr and target velocities in the range of 800 to 950fps-what bbl twist would I most likely pick to achieve the optimum accuracy?? Thanks for opinions,suggestions and tips. Ernierod1 Link to comment Share on other sites More sharing options...
SRT Driver Posted August 20, 2007 Share Posted August 20, 2007 Am considering building a 9mm BE target pistol on a 1911 platform. I have choice of 1:16 twist or 1:32 twist. If I am going to be using bullet weights in the range of 115 to 125 gr and target velocities in the range of 800 to 950fps-what bbl twist would I most likely pick to achieve the optimum accuracy?? Thanks for opinions,suggestions and tips. Ernierod1 Most 9mm / 38 Super Bianchi shooters choose 1-16. Bianchi is not as accuracy oriented as BE (4" X ring) but the ability to shoot a 1" to 1.5" group at 50 is necessary for both games. While some state that only 32 twist is necessary, 16 twist works pretty well for 115 to 125 gr bullets at around 1000 fps. 32 twist might be fine for a 115 at 1400 fps but not at 800 fps. Doug Koenig used to use 1-16 in his pistols..don't know if he still does. Torque and velocity loss with increased twist has less of an effect at <1000 fps than at 1400 fps. Rock River puts a 10 twist in their PPC 9's but that pistol was designed around 147 gr bullets. I suppose it couldn't hurt but it is expensive to experiment. Maybe talk to some of the Beretta Service pistol builders and see what they think. Hope this helps. Link to comment Share on other sites More sharing options...
Canuck-IL Posted August 20, 2007 Share Posted August 20, 2007 Can't find the link right now but as I recall, NSK, a commercial reloader, did some extensive testing that was reported on the BE forum ... he ended up recommending the KKM 1:32 with (I think) 115 pills over VV320 with reported under 3/4 inch 50 yard groups. You might find the reference by digging around the BE forum archive on google. /Bryan Link to comment Share on other sites More sharing options...
revchuck Posted August 20, 2007 Share Posted August 20, 2007 Ernie - My gut feeling - I don't have any data to support it - is that a 125 grain bullet at those speeds would be right on the edge of instability from a 1-32" barrel. I'd go with a 1-16" twist; it also gives you the option of shooting 147s at ~700 fps, which would be like shooting a Clark wad gun without the smoke and with much cheaper magazines. Link to comment Share on other sites More sharing options...
wide45 Posted August 20, 2007 Share Posted August 20, 2007 http://www.schuemann.com/Content/twist0.htm Link to comment Share on other sites More sharing options...
ernierod1 Posted August 20, 2007 Author Share Posted August 20, 2007 Thanks all. Will probably go with a 6" Kart and a 1:16 twist. I feel at reasonable target velocities and 115g to 125gr-9mm bullets-a 1:16 twist will work. Gut feeling tells me for a 1:32 twist, one would have to have bullet exit in excess of normal target velocities-just my personal feeling. Ernierod Link to comment Share on other sites More sharing options...
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