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View Full Version : Plain base vs gas check with coated. Velocity AND pressure



smokesahoy
01-24-2014, 05:00 PM
So we have various threads going over if you coat with a gas check vs without, and it has been addressed that if it is a GC style you still must use a GC. How about plain base styles where the base is coated? Will this get around gas checking and still allow velocity and pressure to be used accurately?

Specifically I was looking at the noe http://noebulletmolds.com/NV/product_info.php?cPath=30&products_id=521&osCsid=4b9sas04c0fnre8nk12e27clt6 plain base as a powder coated in mosin nagant using jacketed data that can take it over 50k psi and nearly 3k fps.

If powder coating precludes an idea that started in 1902 that would be great. 1 less step.

leadman
01-25-2014, 12:40 AM
The issue you are going to have is not only the base of the boolit but the strength of the alloy. When the pressure gets higher than the alloy can take the boolit deforms from its original shape along with the possibility of stripping in the rifling.
Richard Lee's Second edition manual has some very good information in it about this and how to predict how much pressure the alloy will withstand.
I have been shooting the 55gr bator boolit in my 223 Rem Contender 23" barrel up to 3,600+ fps. To do this I cast the boolits from linotype and then heat treat them. I have modified the baking procedure to maintain most of the heat treated hardness.
With the Hi-Tek coating there is little smoke so when I was shooting increased powder charges I noticed there would be a large puff of light grey smoke out of the muzzle along with a dramatic decrease in accuracy. Hardening the alloy changed the point where this occured.

popper
01-25-2014, 12:06 PM
Smokes - I have been testing that approach in 30/30, but nowhere near 3k fps. My conclusion so far - forget the PB, use a GC design sans GC. Tested the RD311 GC 2 groove (~1800) vs a 31-165B sans check(16-1800). 16 gr 2400 vs 30 gr LeverE - almost same accuracy @ 50 yds. RD311 PB was LOUSY - I can't cast 'perfect' bases. Same alloy in all. As soon as I get a new mould from Tom, I'll report more on this.