First time loading 10mm

[Throttlejunky]

Loading some wfn 200 gr hardcast. Never taper crimped before, but have read on it. Have the lyman 3 set die with taper crimp. Using a g40 with lone wolf barrel, heavier spring and all metal guide rod. Slugged barrel at .401, bullets are .402. Lubed and gas checked.
Starting with 7 grains of longshot. New starline bass. Large pistol primer. Max load is 8.2.  Any tips on oal, crimp, powder increments, or anything else you wish you knew when starting? I've loaded 45-70 and .44mag, But still new. I can post details of bullet if needed. I have a mentor who has helped me get started,  trying not to wear out my welcome. Using for target, whitetail,  and black bear backup when bowhunting. Thanks!

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[Kenk]

Welcome Throttlejunky, you've come to the right place for the info you are seeking, Enjoy!!!

[The_Shadow]

Welcome to the forum ThrottleJunky!  The thing I look for is on the very edge of the casing mouth is a shine where it contacts the tapered section of the die as it closes the case against the bullet.

These bullets being 0.4020" and seated inside the casing, the casing will likely measure 0.4225" - 0.4230" as the bullet sets but the very edge of the case mouth you will want to see about 0.4220" - 0.4225" as you measure with the knife section of the calipers.  Smaller bullets will show a little smaller in both areas.



When case expanding you will want the bullet to just start inside to preven the alloy from shaving as it is seated...


You will want to seat the bullet without any crimp being applied while the bullet is fully seated.  If the casing starts to close inward while the bullet is seated it will shave or snag the bullet alloy.
Crimps should be done without any bullet motion in a separate step, this gently squeezes the case against the bullet to aid in securing the position and aid in smoother feeding when cycling.!

[Throttlejunky]

Excellent info. Thank you. How critical is the taper crimp in relation to pressure? I can deal with poor accuracy if I end up with a learning curve, but I have grown quite fond of my fingers....and my wife (for unknown reasosns) thinks I have a pretty face. I'd rather not mess that up. Is it accurate that seating depth has a far greater effect on pressure, and that or a powder mistake (charge or powder mix up)is what will cause an pressire issue that exceeds flattened/flowing primer or brass bulges? I'm very new to this and understand when something goes wrong, it can go very wrong. I have no feel for what is black and white and what is gray with reloading.

[The_Shadow]

At the load you're using everything should be just fine...
Double Tap also was loading with LongShot 8.2 grains back in 3/2014

http://10mm-firearms.com/factory-10mm-ammo-pull-downs/double-tap-200gr-wide-flat-nose-hard-cast-gas-checked/msg28270/#msg28270

[Throttlejunky]

Excellent. Much appreciated.

[tommac919]

I always do the PRESS test on my rounds when setting up a taper crimp...
Measure the OAL and then forcefully press against the work bench... measure again to make sure you weren't able to press the bullet into the case any.
If no change and there is  no notice of  shaving bullet or ripple of brass, taper crimp is set good for me.

[Kenk]

Really good idea, Thanks!

[Throttlejunky]

Thanks for the tip

[Univibe]

A.  40 years experience here; I recently got a 10mm and started loading. 10mm is no different from any other semi-auto cartridge.

B.  One thing I do for all my pistol loading, is that I use a four-die set.

1.  Size and decap.
2.  Expand / flare.
3.  Seat the bullet.
4.  Crimp.

This means that the seat/crimp die that comes with the kit is set to seat the bullet only, and not crimp.    Then I buy another seat/crimp die ($20), and pull out the seating plug, and use it to crimp.   I think it's better to separate the two operations.  This adds another step to the process, but so what?

C.  Also, the taper crimp will not substitute for case tension on the bullet.  In other words, make sure you don't get bullet setback during the firing cycle, which can raise pressures seriously.   If you do, you need a tighter than stock sizing die (RCBS will accommodate you).  You can't crimp your way out of this problem (or the opposite problem, bullet jump, in revolvers). 

D.  I use Accurate Arms #9, which most feel is THE 10mm powder, for heavier loads, i.e. 180 grains at 1300 or so fps.    A faster powder, AA5, can work fine for FBI-lite loads.  AA powders also meter superbly in powder throwers.

E.  Starline brass is first-rate.   I'd recommend running even factory-new Starline through the sizing die, just to make sure.

F.  The bullet seating plugs supplied with  dies are pretty generic.  If one doesn't fit your chosen bullet, send $20 to RCBS (other companies may do this too) and some sample bullets.  You will get a custom made seating plug that fits your bullet exactly.

G.  Won't hurt to get a case gauge  to test your output.    Easier than using the barrel of your gun.

H.  One thing I discovered quite recently is the RCBS bench priming tool.   I highly recommend this $80 tool as opposed to priming on the press during the expand / flare cycle.    It adds yet another step, but so what?

I.  If your chamber does not fully support the cartridge (Glock, Colt Delta Elite, others) watch for case bulging.

J.  Wash those cases!   I skip this with revolvers, but I do the following with semi autos:

1.  Throw cases in a large bottle with a bit of dish soap.
2.  Shake well.
3.  Pour cases into a plastic spaghetti strainer, and rinse thoroughly under running water.
4.  Let dry.   Helps to put them out in the brutal TX sun all day, or put them on top of your clothes dryer.
5.  When thoroughly dry, tumble them.
6.  Repeat steps 1 through 4.   

Now, you're ready to reload.  Your carbide sizing die will thank you.  I think 10mm cases get dirtier than .45 ACP.   .45 deposit themselves politely in a neat pile on the concrete surface of the range.   Tens fly about three miles and bury themselves in the mud when they get there.

[Graybeard]

That is Excellent advice from Univibe and I concur. I use Dillon 10mm carbide dies and have found them to be just about perfect for my 10mm loading. The sizing die gives me a slightly wasp wasted case and provides excellent case tension on the bullets I typically use.

I also use Hornady One Shot case lube on all cartridges with thicker case walls, 10mm, .44mag, etc. Makes it much easier to size them. I don't put them in a bag, spray, and shake them. Just stand them on a plastic tray and spray from 2 directions for about 2 seconds each. It dries enough to handle in about 2 mins.

To Univibe: have you ever considered the SS media cleaning system? I've used it for years now and my brass comes out spotlessly clean no matter how dirty it is. It's really economical once you make the initial purchase. A little Dawn dish soap and Lemishine for each batch is all you need. The SS pins last forever. You could skip the dry tumbling step and utilize that blazing TX sun to be ready to reload in the same day.