275 TSX and bullet creep

[Hoot]

their regular 450 factory crimp die which crimps at the case mouth.

I have one, just never got around to trying it.

I've modded a few of the Lee 450b FCD to side crimp and IIRC (remember my last blunder) the width of the un-modded FCD may be wider than the width of the TSX driving band grooves, so it may not get down into one of them. The stab crimp will impact a load recipe based on the taper crimp but only a grain or so. Once upon a time, I actually tried stab crimping down into both grooves at the same time to see how much more velocity it would generate. Loaded up 5 ladder rungs in half grain increments and wound up aborting the experiment after the first ladder rung. It was a lot like a controlled detonation! Some ideas pan out and some don't.

Hoot

[PHR87]

Ha, I’m sure that was exciting! That thread is actually what made me wonder about changing the recipe based on doing the side crimp. But if I do go that route, I’ll drop a couple grains and build back up a bit.

I’ll report back about what I see tomorrow at the range.

[PHR87]

I went to the range yesterday and it was frustrating to say the least. I think I have a couple of issues to chase down, but my groups were all over the place. First, I have long suspected that my scope is on the fritz. It started life on an inherited 7mm Mag and I’ve had trouble with groups on every rifle it’s been used on. I would get a couple shots touching and then a few flying 5 or 6” away. My groups with the Hornady black were 3-3.5 MOA. This is off of a bench with a lead sled.

So I think I can’t really use any of my groups as great indicators. I was only able to work up to 38.5 grains of lil gun, but I was not seeing any crazy signs of pressure. My brass went from ejecting at about 3/4 o’clock to about 2 o’clock, But cases/primers/head growth were all looking ok. I have loads built up to 39.5 gr.

There were a few rounds where I noticed the bullets were seated a little bit wonky, so I pressed them on the table and they straightened out easily. A couple were loose enough to move by hand! This is with a .472” taper crimp at the mouth, into the grove. It seems my neck tension is insufficient, to say the least. I ordered a 450 bushmaster Lee FCD last night, along with a scope. We’ll see what comes out of that.

How much pressure increase should I expect due to that crimp? I’m hoping to do a fairly light stab crimp along with taper at the mouth- both into the driving bands. Maybe drop back down to 37 grains-ish and work up from there?

Thanks guys!

[MOOSE EARS]

I see you are using Hornady dies? Your bullets shouldn't be wonky! Are you expanding the case mouth with a bell?

[SAWMAN]

Case mouth expansion is a slow,trial and error process. A very little at a time has been my expierance . . . after mic'ing the exp ball. --- SAWMAN

[PHR87]

I didn’t expand at all. Just sized the once-fired Hornady brass. Didn’t seem to miss it either, with the .4505 TSX bullets..

[MOOSE EARS]

I use the same bullets and Hornady dies and they are tight in the case, no wonky. I also side crimp with a modified Lee FCD. These are some of my most accurate rounds with 40gr of LilGun. You may have bad dies.It can happen. One question, did you chamfer the case mouth to start the bullets?

[PHR87]

How would I know if the dies are bad? I presume you’re talking about the sizing die? They weren’t all loose, only a couple. But all the ones that I slammed forward did creep forward.

I gave the mouth a very light and brief chamfer before pressing.

[Hoot]

Were all the brass confirmed 1-fired? I ask because brass work hardens a little more every time they're fired and resized. That results in what we refer to as springback. In many calibers, including this one, it manifests in inconsistent neck tension. I track the number of times every case I own has been reloaded because of that. Process Link Eventually, they need to be annealed to remove the work hardening. If you can't confirm the pedigree of brass you bought second hand, assume that they are mixed-fired and start off on the right foot by annealing them after you clean them up.

Hoot

[PHR87]

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.