Hey guys, I have noticed as I have been working up my loads that the HP more is getting partially crushed/closed at the bullet seating stage. This isn't happening with the HST. Bell is good, and I am loading in new starline brass that has been resized before loading. I am using Lee dies.
Any thoughts? Do I need to buy a different seating plug or something?
I only see this with compressed powder charges (several seating anvils). What's the bullet weight, powder, charge and C.O.L.?
Good thinking, I'm trying to seat a 200 grain XTP over 13.2 grains of AA#9 at 1.26" COAL. I will load one with less powder and report back. (this is the most recent Hornady max book charge)
Yeah, you're compressing. At 1.260", AA9 begins to compress at about 11.5 gr. with the 200's.
This places you in a difficult situation with that load. It's above what I'd consider max, so there's not a lot of room to work with. If you manage to seat the bullet w/o deforming, it will seat deeper in the case, which changes the pressure considerably, especially when compressed to the point of bullet deformation (it's exponential, compared to having less/no compression). If you haven't shot these yet, you'll have to rework the load (start over). If you've been shooting them, "fixing" the bullet deformation will change the cartridge characteristics, and you'll have to rework the load. The problem with bullet deformation, it is hardly ever consistent in the amount of deformation, which leads to pressure, velocity, accuracy and flight variations, due to varied bullet base depth.
I use a method of "pre-compressing" with some large magnum pistol and rifle loads, but I DO NOT recommend this with AA9. The powder starts out very dense with fine granules, with very little loft. Excessive compression will essentially press it into a pellet, which dramatically changes its burn rate and pressure map. This doesn't work with AA9, in my experience.
If you aren't using a magnum primer, I suggest you rework the load, use a magnum primer at a lower charge. It doesn't always work, but it will often increase the consistency with slow powders, allowing a bit of velocity loss in trade for a more effective cartridge. There are a few powders I use only magnum primers with, and AA9 is one of them.
Or, choose another powder.
You were right, it was the powder compressing, I loaded one up without any powder and it went in smoothly. I only loaded two like that, I will pull the bullets and start over. At 12.5 the bullets were a little firm to seat but didn't deform the tips noticeably, at 13.2 they are about 50% closed (no good) and take noticeably more effort to seat. I didn't even give 13.2 a second thought before attempting because it is a book load and I've seen where others have supposedly loaded 13.5+ without any mention of deformation (there obviously was some).
I will rework the load back up to 12.5 with a magnum primer and see how that goes. 1,200 out of the factory BBL and I will be happy. I should also be able to get there with 800x (with hopefully a little bit less than UW uses for ~1250). I already ran 9.0 800x and only got ~1150 FPS. The Underwood load seems to be 9.2-9.4... will continue the workup carefully. The first time I fire any of these high power rounds I'm wearing gloves and have the magazine out of the gun just in case! :-\ I know that others have done more but like they always say... different lots of powder, different gun, different temperature, etc. can give vastly different results. This is why we work up to max loads.
I got right around 1225 fps with 8.8 grs Longshot last weekend with a 180 XTP and ran out of time to go higher. Longshot may be a possibility also.
Are you using a Round Nose Seater Plug or the flat one for Trun Cone Bullets ?
The Round Nose plug will scrunch your Hollow Cavity
Quote from: DenStinett on May 31 2013 11:41:13 PM MDT
Are you using a Round Nose Seater Plug or the flat one for Trun Cone Bullets ?
The Round Nose plug will scrunch your Hollow Cavity
That's also a good thought. I just pulled the plug out of my Lee die and sure enough it is rounded (hemisphere).
Unfortunately it isn't reversible.
Are the other plugs completely flat?
I don't know about Lee but my Hornady set came with a flat and a rounded seater plug. I believe in other calibers RCBS dies also do as well for pistol cartriges. Lee should have on.
It only came with one plug. My friend will machine me one and I'll try it out.
My Redding 10mm dies come with 2 plugs. One flat and the other not.
Quote from: DM1906 on May 31 2013 07:43:03 AM MDTYeah, you're compressing. At 1.260", AA9 begins to compress at about 11.5 gr. with the 200's.
With my #9 at 1.260" I have to be at 12.6 grains before compression starts using a 200gr XTP. I know #9 has changed over the years though.
Quote from: REDLINE on June 01 2013 06:11:53 PM MDT
Quote from: DM1906 on May 31 2013 07:43:03 AM MDTYeah, you're compressing. At 1.260", AA9 begins to compress at about 11.5 gr. with the 200's.
With my #9 at 1.260" I have to be at 12.6 grains before compression starts using a 200gr XTP. I know #9 has changed over the years though.
Compression = any point during bullet seating, after the bullet contacts the powder.
The bullet can be seated deeper, and varies depending on the loft of the powder, which is compressing. AA9 begins compressing easy, then hits a hard wall. It's a dense powder with compression characteristics similar to other powders, typically Magnum pistol/shotgun powders.
"Forcing" powder compression, such as using a "custom" seating anvil to allow more compression, is compressing the powder beyond its maximum compression rate. A deformed bullet, when it isn't deforming w/o compression, is an indication of over-compressed powder. This is acceptable in some cases, so caution is recommended (work up VERY slow). AA9 is fairly safe, as you can't get enough powder, compressed or not, to cause an overpressure in 10mm, using almost any bullet.
Right, and in my experience my #9 doesn't touch a 200 XTP at 1.260" till I'm at a charge weight of about 12.6 grains. At 14.0 grains I can't seat below 1.263 (actually slightly more since the XTP is already lightly crushing on top).
Quote from: RMM on June 01 2013 07:46:46 AM MDT
Quote from: DenStinett on May 31 2013 11:41:13 PM MDT
Are you using a Round Nose Seater Plug or the flat one for Trun Cone Bullets ?
The Round Nose plug will scrunch your Hollow Cavity
That's also a good thought. I just pulled the plug out of my Lee die and sure enough it is rounded (hemisphere).
Unfortunately it isn't reversible.
Are the other plugs completely flat?
RCBS has both flat and round in there standard Three Die Carbide Set
They also offer some specialized i.e. Gold Dot Plugs
But when it comes to the High End HP Bullets, you gotta use that Flat Plug
The Round Plug will close-up that Hollow Cavity