After abysmal attempts at dialing in a load with flat base bullets, I switched to boat tails and WOW what a difference. The rifle: an Interarms Mark X. The chambering: 7X57. The bullets: 145 speer BTSP and Berger 150 Classic Hunter.




Finally, a healthy dose of IMR-4350 makes it a MOA shooter with both sets of boat tails.


Also, an interesting note: Friend of mine gave me some collectable tins of old Herter's powder, likely from the 70s and as old as I am. Three out of the 4 cans were/are still sealed. After lots of research and evaluating powder status and finding antiquated load data for it on the interwebs, I loaded up 3 rounds with it. Wouldn't you know that it, albeit relatively slow, shot the best group! Crazy...


The good news is I'm not going to be shooting this one a country mile, so MOA has made it very acceptable for the style of deer hunting I do. The trigger is nice and crisp, and it's a great classic styled rifle with the handsome walnut and deep, almost black, blued steel. I may continue to tinker with it to try to narrow it down a little more, but I'm more than happy with those groups, especially since the flat bases speers were toggling back and forth between 3 and 4 MOA. I count it as a win.

Nice shooting!

I really like threads like these. Glad you found some loads that will work, and good to see that old powder get used.

Cool deal! I think Herters 102 was actually made by Nobel for Scot powder. H102 is 4895ish in burn rate if my info is correct so the speed won't be 4350 like. I kid .270 shooters that the 7x57 was O'Connor fave caliber...Mrs.O'Connor.

Looks like a winner.

4350 is the cat's meow for the 7x57 IMHO.

Never seen any of that Herters powder , oh and good shooting

I have 101 and 102.