55gr. bullet with Win748 loads

gushulak

gushulak

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Researching snakes somewhere in SW Manitoba
Anyone loading for an AR using Win748 powder?

I am developing a bulk load and can't seem to get the velocity up and I am .2gr. short of a max load. Haven't tried anything over 26.2gr but my velocity is still only about 2500fps. My chrony results are slow but the load is statistically looking good compared to the lighter loads I have tried. Because I am using military brass can I push it a bit more or should I stay put? Heard from one fellow on CGN that he uses 27.0grs. of 748 for his load. Any other loads I should try out?

I would like to duplicate the WWB load at 2950fps out of my gun, details of my loading is below, ANY help or suggestions on a tried and true load using 748 would be appreciated.

Firearm-Sabre Defence AR15 (14.5"bbl)
Brass-IVI once fired, match prepped
Powder-Win 748
Bullet-Hornady 55gr. FMJ-BT
Primer-Win Small Rifle
COL-2.200"

Thanks guys!
 
I used W748 and 55 grain pills for years and 27 grains was my standard load. It never showed any pressure signs and was extremely accurate. Work up to at your own expense. I even went to 28 grains while testing and had no pressure signs, but accuracy was not as good. I also use WSR primers.
 
I've been running 26.5gr 748 under 55gr Lake City FMJBT out of my XCR and the velocity average was 3011 fps. Thought my barrel is 4" longer it shouldn't make that much difference. Perhaps the lighting on the cronograph was affecting its readings?
 
I forgot to mention that I always give them a good crimp too. I haven't chronied them without the crimping, but I am easily breaking 3000 fps.
 
I am giving them a good crimp and the chrony results I trust. Other proven loads chrony the same (I use some as a baseline). I am just not getting the velocity at this point and thought using the thicker IVI brass I would be able to back off the charge a bit to obtain the same velocity. Haven't thought of using magnum primers as I have tens of thousands of SRP's.
 
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