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Posted: 3/17/2007 10:29:51 PM EDT
| Can someone please advise what is the twist rate in my Sig 550 rifle. It is a "deautomated" P model with green furniture ex Swiss army. I know that the 550-1 model is 1 in 10 and the 550-2 model is 1 in 7 but I am not sure which twist rate the ex army models use. I checked a friends brand new PE90 and that is marked 550-2 but no such markings on mine. Anyone any ideas???? She shoots 55gn ammo pretty well but I havent tried her on anything heavier. |
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Use a stainless steel cleaning rod. Insert it into the breech end with a patch in place. Push the rod in a short distance such that you know it is engaging the rifling. Mark top dead center with a Magic Marker or piece of tape on the cleaning rod, marking the point at which you start on the cleaning rod. Push the cleaning rod in until you have one complete revolution of the top-dead-center reference marking. Mark the point at which you stop. Measure the distance between the two points. Provided you only mark the distance between one turn, it will be 1 turn in [whatever you measure] inches or millimeters. Good luck. |
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Thanks for that - I'll give it a go! The 550's have only recently come available - I never thought I'd get my hands on one. Some (roughly 6) were brought in new by one of the big gun stores in Auckland at NZ$6k each - this is my friends rifle. Another dealer arranged to get some through a german dealer (I think this is correct) and again only a handful were involved. Probably no more than 30 in the country, if that. Love shooting mine - managed a 5 shot, 3 inch group at 500 metres yesterday using the iron sights - total fluke but good fun! |
Not exactly. 55x-1 denotes 1:10 twist. 55x-2 denotes 1:7 twist. There are 550-1, 550-2, 551-1, 551-2, 552-1, and 552-2 rifles.
It will work just fine; the 1:10 twist will stabilize a 62gr. But I would not use a suppressor with a 62gr/1:10 twist combination as you risk a baffle strike or at least a baffle or endcap rub. |
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