I now believe I have the correct information to share with the forum.

I need to thank a forum member Grouse for helping figure out the differences in the bullets I was using versus the bullets he was using in his new SSK Mongrel rifle.

The picture below shows the difference between the 265 advertised on the website and the 260 Mongrel owners receive with their new Mongrel rifles. The website indicates the sale of .458x265CF brass bullets. The bullets sent with the Mongrel 260 grain and I believe the difference is in the thickness of the powder cup at the bottom of the bullet.

The picture below shows the difference I have discussed. The picture on the left is the 265 grain bullet that I received from the SSK Website. The bullet picture on the right was furnished by Grouse for my comparison. Note the difference thickness of the Powder Cup wall. The thicker wall on the 265 could interfere with the proper expansion of the base to seal gas behind the bullet. The cup on the new 260CF is noticeably thinner and will expand the bore.



I venture to say this why SSK put the bullet in a sabot and is selling it for a 50 cal. ML. And once again I will say the bullet shoots extremely well for me from a 50 Knight U-Lite.

This is a Ballistic sheet ran for the bullet shooting 120grV of BH-209



Hope this helps explains my efforts.

Mike that's good info but my question still remains. Can you size them down to .451" without issue for the .45? You got me hooked on the copper ones

Bronko, I was unable to size the brass ones down, but I am using an inexpensive Lee sizing die,

If or when the Mongrel bullet makes the website there is a good chance that will resize;

Thanks Mike....Doesn't that suck that you find a bullet that shoots fantastic and its no longer made? I hope Dave starts making them again.

I think at some point he will offer the new Mongrel brass bullets to the public and they should be able to re-sized so we can use them in a 45.