450Bushmaster.net

Al,
I did not check rounds twice in a row to see if the bullets creeped even further. I will give that a try next time I shoot. I rode the bolt home after I measured the creep and loaded them back into the magazine. Honestly, if I had a bolt action, I would load them longer and use the 39gr load. They were nicely grouped.

posting for OP

Thanks for posting Al,
The 39 gr looks like 2 shots, but it was 3. I use 2" Styrofoam zipped stripped to 2 garden T posts and use toothpicks to hold the targets. works great!

Accuracy nodes every 2.5 grains.
Hmmm.
I find that very very interesting.
I found that same anomaly with Lil Gun.

msd4141 wrote:Al,
I did not check rounds twice in a row to see if the bullets creeped even further. I will give that a try next time I shoot. I rode the bolt home after I measured the creep and loaded them back into the magazine. Honestly, if I had a bolt action, I would load them longer and use the 39gr load. They were nicely grouped.

Did you load any higher? I was ok with my pressures at 40gr of lil gun, but obviously keep an eye on them. My groups started to tighten up at 39 but 39.5 and 40 have consistently been the best. And there’s little variation between the two in terms of accuracy (precision) and speed. So that’s a desirable load because it’s tolerant of variations.

I’ve been getting higher speeds through my chrono, but am also shooting at 6500’, so that’s not terribly surprising. They’ve also been very warm days, so we will see how sensitive the LG is to cold temps.

What scopes are you guys using? I’m using a 2-7x hunting scope so I know that’s a limiting factor for me too.

EDIT: I just noticed that both of you are using H110 and I’m using lil gun, so ignore my comment about comparing grain amounts.

Msd- I went back and reread your previous post about creeping and pressures. Have you tested your rifle at the longer seating depths? You said you were uncomfortable with the bullet creeping from 2.32”. Try it out and see!

As I mentioned before- my second shot (with bolt slamming forward) only opened up 1/4-1/3 MOA, so I’m perfectly comfortable with that. I’m hoping to not need a second shot though! 275 grains of fury- screaming along at 2300 FPS or so- will almost certainly be devastating! As long as I do my part. That’s actually the much bigger variable!

I was playing with seating depths and found no pressure issues even when loaded out to 2.375”, which was the longest I can fit in my mag well. Ymmv.

PHR87,
I have not loaded over 39 grains yet. I picked the 36.5 H110 grain load due to the accuracy I had while testing. I loaded up 20 more rounds to a COAL 2.25 and tested them again just to verify for my hunting round accuracy. The group opened up somewhat. I'm not sure why as all I did was a dry barrel swab after the load workup, all other components the same. The first shot seemed to be a flyer, then the next 3 were just over an inch. All of the shots will work for a deer as even with the flyer, it was just over2 inches.
I have not tested live rounds loaded to 2.32 ,except while riding the bolt home, because when I had dummy rounds slam home the bullet creep seemed to be significant enough to get me close to the lands. I get nervous because I have read that when you get close to the lands, your pressure can spike fast!! I have some leftover workup rounds loaded to that length and I will load the mag up and measure the length after they auto load from firing a round.

That 275gr should be around 2.450 to the lands.

This one is seated 2.400, that's where I got best accuracy in my #1 and 700.

Al,
Am I missing something? When I load into the cannelure closest to the tip of the bullet, I'm at 2.320 and that round of yours looks like it is loaded way longer than .080 difference we are talking about. I also measure 2.450 to the lands in my Tromix barrel in my bushmaster upper.

msd4141 I believe Al's pic is a 275Barnes XPB which has 3 driving bands .The TSX bullet, while being the same weight and profile only has 2 (the bottom 2 nearest the base).