Pursuit of an inexpensive accurate super bullet - 125 tnt speer

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Netpackrat
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Re: Pursuit of an inexpensive accurate super bullet - 125 tnt speer

Post by Netpackrat »

Sounds like you have done a lot more extensive testing than I did. My goal was inexpensive range ammo with decent accuracy from my carbines, and once I had achieved satisfactory performance I stopped there. Either way we are only talking about a 15 thou difference in OAL and I wasn't trying to tailor my load to a specific rifle.
gomeybear
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Re: Pursuit of an inexpensive accurate super bullet - 125 tnt speer

Post by gomeybear »

My trim length is still within SAAMI spec of 1.348-1.368. Anyone find that accuracy drops off when cases are trimmed to the lower spec?
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Netpackrat
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Re: Pursuit of an inexpensive accurate super bullet - 125 tnt speer

Post by Netpackrat »

gomeybear wrote: Sat Jan 02, 2021 1:51 pm My trim length is still within SAAMI spec of 1.348-1.368. Anyone find that accuracy drops off when cases are trimmed to the lower spec?
In and of itself, the shorter trim length probably isn't going to have much effect on accuracy one way or another. But as demonstrated by Dellet and 20X11, how close you are seating the bullet to the rifling matters. And given a short, stubby bullet like the TNT 125 that limits how close you can seat it to the lands under the best of circumstances, trimming .010" (or .018" really) shorter than you absolutely need to will reduce your possible envelope of OAL options by the same amount.

It's entirely possible that too short of an OAL is the reason my M7 made shitty groups with this bullet. I never did any additional testing on that because my load with the TNT met my objectives for it. Would have been a cool bonus if they had shot decent from the bolt gun too (in general, that rifle does better with subs than my ARs, but is mediocre with supers), but that wasn't an important criteria so I just don't know. Some rifles also just don't like some bullets. I wasn't willing to put in the time and effort to pay for that knowledge, and again, like I said in my earlier post, I seated it out as far as I was willing to given the limited neck engagement available. At the same OAL as I am running but the shorter trim length, you are already at .010" less engagement than my load (IIRC, I was using 1.360" as well).
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