I loaded some 260 grain Cast Performance Bullets using 34 grains of Reloader 7.  My chronograph shows an average of 1,950 fps.  The bullets are .376 diameter and have a gas check.


Can I get more velocity out of this bullet using this powder or is this about the top end?  I'm not showing any pressure signs.

I think you might be close to the end of the road with that combo.  For heavy cast bullets in my Win BB 94 .375 I've switched to AA1680 and I use .38-55 brass, which gives about 3-4gr more case capacity.  Still working on load development, but I think others on this board could give you more details about their experiences with this combo.

Thanks for the response.  Accuracy seems to be good with this particular load so I'm thinking about trying it this weekend.  I figure this load has plenty of punch for deer and hogs so I doubt I will try to get anymore out of it.

Matt,

What trim length do you use for the 38-55 brass in your 375 Win BB?  I too have an older model and want to use this brass... I have heard some using the 38-55 trim length, but am hesitant to do that, guns are too expensive for me!

Thanks, Jim B

Chrisf,

I have no experience with the Cast Performance bullets in this caliber. *But using the BTB 250 gr LFNGC over 35.7gr of Re7 in 38-55 cases I get 100 fps more out of my Marlin than what you're seeing. *I get the same velocity using 35.5 gr of Re7 in fireformed 30/30 cases. *These are sized to .377. *I've only had to trim the 38-55 cases once and then I used the trim-to-length for 38-55 (2.118 I think). *Of course there are a lot of variables here so don't try this without easing into it.


In a posting regarding max velocity for the 375 Marshall mentioned that AA1680 produced the top velocities in his tests. *I have yet to try it. *One of his loads that I recall (using Re7) ran at about 2250 fps. *These postings are buried somewhere down in this forum (see page 5 for one of them).



(Edited by bartmasterson at 8<!--emo&:0--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'><!--endemo-->3 am on Nov. 17, 2001)

All,
I have a Ruger #3 in this Cal. and use a 260gr. Gas check sized .377. My most accurate load to date is 32gr. of 3031 with the bullet seated to 2.59" . This load groups under 2" at 100 yds. 1 have been up to 34gr. of 3031 but that load is compressed (alot).
My next try will be with #1680 and i will keep you posted.
I have used up to 36gr. of #1680 with the 220gr. Hornady with no problem and still working up slowly.

oldpete