275 TSX and bullet creep

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Re: 275 TSX and bullet creep

Postby Hoot » Fri Jun 12, 2020 11:33 pm

PHR87 wrote:Thanks hoot, they’re definitely once fired in my rifle. I bought a 150 round can of the Hornady black. I have about 90 rounds fired through it.


OK, just grasping at straws. IME, Hornady has been very helpful and responsive to my concerns. I can't tell you how many things they've sent me free of charge once I spoke with a technical representative about some problem with their dies. That's why I'm a big fan of theirs. Give 'em a call and explain your observations.

Keep in mind that not all brass are created equal. Again IME, bulk quantities tend to come from different, end of run lots of brass, with possibly different initial hardness which equals different springback. Now that's really grasping at straws. :|

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Re: 275 TSX and bullet creep

Postby PHR87 » Sat Jun 13, 2020 11:14 am

Thanks, after reading more and more on here with the common issue of insufficient neck tension, it seems a stab crimp May be my only option. I could see there being enough tension with the larger .452” bullets, but the TSX are all .4505” or so.

The 450 Lee crimp die should be here in the next couple days and I hope to modify it to make it work. Then I’ll start over with somewhat lighter loads and work my way up again.

Also, we’ll see if the scope was a confounding factor as well. I suspect that it is, especially with the Black ammo grouping so poorly off of a sled. I also cleaned the snot out of the bore with Hoppes and Barnes cr10 and it didn’t change much.
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Re: 275 TSX and bullet creep

Postby PHR87 » Wed Jun 17, 2020 5:35 pm

Update today:
I finished up the 2 remaining steps of my ladder with new scope. My best group was 1.6 MOA, (4 shots) which had a SD of 6 FPS! I don't think I believe the chronograph on that, but I don't have much choice!

I also measured the factory black rounds and noticed that they did lengthen when chambered at full force. So, I'm wondering if the bullet creep even matters much? I think I'll do an experiment with 2x 5 rounds of the 39.5 gr group- one with riding the bolt forward and one with slamming it forward.

I'd still like to see better groups than 1.6 MOA, but I'll play around with the seating depth some more. I also plan to load some more TSX up with a light stab crimp into the last groove and taper on the front groove/band.

There's also the possibility that my rifle just doesn't like the TSX bullet, or lil gun powder. Although, I can't really trust any of the groups from my previous testing with the old scope. Has anyone tried any of the Maker bullets? It's another mono that seems like a good candidate.

Open to any thoughts or suggestions!
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Re: 275 TSX and bullet creep

Postby MOOSE EARS » Thu Jun 18, 2020 4:50 am

Don't give up on either the bullet or the powder, especially, yet. Try seating the bullet down to the top of the last groove where no groove shows when seated. Seat as deep as the bullet grooves allow and try again. With 40gr of Lilgun, I'm shooting sub-moa groups. What barrel do you have and how clean does your trigger break?
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Re: 275 TSX and bullet creep

Postby PHR87 » Thu Jun 18, 2020 7:59 pm

That’s pretty much where I was seating them, about 2.335”. Is that about where you are?

I have the bear Creek arsenal upper and a pretty decent trigger. It’s not the cleanest, but it’s better than mil spec! I’m shooting from a lead sled, so I don’t think the trigger is contributing much..
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Re: 275 TSX and bullet creep

Postby MOOSE EARS » Fri Jun 19, 2020 4:29 am

They need to be seated deeper, around 2.20". That will make a difference in all you're experiencing.
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Re: 275 TSX and bullet creep

Postby PHR87 » Sun Jun 21, 2020 9:52 am

Moose, do you crimp them at all? That advice seems to run counter to what some of the others are doing- seating longer and then taper or stab crimping.

And no pressure issues in an AR with seating deeper and 40 grains of lil gun?
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Re: 275 TSX and bullet creep

Postby MOOSE EARS » Sun Jun 21, 2020 1:28 pm

I SIDE crimp with a modified 45/70 Lee FCD. When I started, there were no crimp dies for the 450BM. I am pushing hard with 40gr and I don't recommend this load w/o careful work-up. But I have no issues with my 1:24 16" Bushmaster barrels. And they shoot incredibly well. My triggers are enhanced with a set screw and JP yellow springs and I know this helps alot with AR accuracy.
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Re: 275 TSX and bullet creep

Postby PHR87 » Sun Jun 21, 2020 1:37 pm

Ok, that makes more sense then. I just modified my lee FCD and haven’t loaded anything up with it yet. I’ll see how those go with varying levels of seating depth and go from there. I got up to 39.5 grains with a .472 taper crimp and the case growth was getting to .0015ish. I’ll back off with the side crimp and work up again.

Thanks
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Re: 275 TSX and bullet creep

Postby msd4141 » Sun Aug 02, 2020 1:33 pm

Hello Everyone,
I finally got around to setting up to load the 275 TSX. I have read, and reread the different posts about this bullet. I am reloading with Lil Gun, or H110 for My AR 15 with a 18" Tromix Barrel. I windowed a mag back in January, and it turned out good. I was setting up my Hornady 4 die set, and loaded a 3 dummy rounds to 2.33 I set my taper crimp die to crimp at .472 driving the taper crimp into the top band that was almost completely buried in the once fired Hornady case that was tumbled in stainless steel media, then full length resized. I did not bell the case mouth as the 275 TSX has a taper at the bottom, and a bell is not needed.I tested the dummy rounds in my AR by cycling from the mag and letting the bolt slam home, like it would in normal firing. The bullet creep was evident on all 3 dummy rounds. About .012 to .014 longer. COAL was 2.33, then went to about. 2.45 after cycling. I don't have a side crimp die. I also tested some dummy rounds with the grooves completely buried with a COAL of 2.25 (as Barnes and Hodgen states) and cycled the dummy rounds, again same thing with the bullet creeping. I decided to go outside and cycle some factory Hornady 250g FTX which COAL factory loads were about 2.52 before testing, and they crept about the same as the TSX dummy rounds .010 to .012 longer with COAL at about 2.64
I guess my question is, should I load to 2.33, taper crimp and live with the creep, or should I loads to 2.25, taper crimp and live with that creep? I know people are loading longer to get more speed from the 275. The barnes and Hodgen sites both list 2.25 COAL with lower charge weights than what I see people are using here. I know that is because the bullet is seated deeper. I'm really trying to figure out what to do. Does the creep matter a whole lot? Should I use the 2.25 COAL and taper crimp and let it creep like the factory rounds? I want to be safe. I usually follow the manuals, start low and work up to be very safe. (I like my hands and eyes ) Thanks for any insight to this, and I will keep reading. Marc
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