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View Full Version : How much difference does a GS make?



qajaq59
11-06-2007, 07:51 AM
I wonder if anyone has scientifically determined how much faster you can drive a cast bullet, and still avoid leading the barrel, if you add a gas check? I've used them for years, but never really thought about it until a non shooter asked me the other day.

454PB
11-06-2007, 12:51 PM
Not a scientific determination, but in my experience, it's about 1300 fps. Now there's a lot of variables there.....barrel condition, lube, powder burn rate and pressure levels, proper sizing, etc.

I've pushed PB boolits even faster without leading, but accuracy starts to deteriorate.

Bret4207
11-06-2007, 08:33 PM
Too many variables to make a concrete estimation. As a general rule for the average gun and load, I'd guess somewhere between 12 and 1500 fps for a PB before big problems crop up. In some guns anything without a GC is suicide and in others you can go bonkers without one up to 2000 fps+. Those are rare, but you hear about them occasionally. FWIW- It seems the larger the bore the easier to go PB.

You could do the experiment starting with a GC design and seeing how fast you can go with a variety of loads. Then open it to get rid of the check and run the same loads. Yes the CG would be slightly different, but you'd have a basic idea.