Should I keep loading? How Do I Verify Taper Crimp?

[dad23honu]

I just finished loading my first 5 bullets. 10mm, 4.1 grains of HP-38 behind a 180gr Rainier Plated bullet. Still have to wait another 6 days to pick up my Glock 20, though.

I have some questions.

1: Should I go ahead and work up some other loads? I have 3 other types of bullets (155, 165, 200) from Rainier. I'm hesitant to do any more because of...see other questions.

2: How do I know if I have a good taper crimp? What does a prototypical taper crimp look like? I'd hate to work up another 95 rounds if my taper crimp is crappy.

3: I'm reading everywhere to start at 10% of max load and work up from there. As I mentioned, I'm using Rainier copper plated bullets. Rainier's website says to use cast lead data or use FMJ data minus 10%. If the book says to start with 5.0 gr for a jacketed bullet. Ten percent less than that is 4.5 gr. Well, because this 4.5 gr is now my "new" max load for the copper plated bullet, I now have to reduce my load to about 4.1 gr. to start. Does this sound too low?

4: If I start out at 10% below the maximum charge, what increments should I be using to go up in powder charging? If 4.1 gr is my minimum, do I go up in 0.1 gr increments to the max of 5.0?

Thanks for your help.

[Ifishsum]

With an auto round, I basically just want to smooth out the flare I put in before seating the bullet. Too much crimp on a plated bullet can cause the plating to flake off. If I can't push the bullet in with heavy thumb pressure and the case wall is straight, I'm satisfied.

0.1 gr is a pretty small jump, but it's also a small spread you're working with. I'd probably jump up 0.2 at a time, but that's me.

[Bullet94]

I got this out of one of my loading manuals -

Taper crimping should remove any flare left on the case mouth from the neck expanding step and squeeze in the case mouth tightly against the bullet. After the flare is removed from the case mouth the case should not be reduced in diameter by more than .001” or .002”. Any more than this, and the bullet will be deformed in this area. Of course accuracy will then be effected. Cast bullets, especially when made from a soft alloy, are particularly vulnerable.

Since your using Hodgdon powder you might check here –

http://www.hodgdon.com/data/pistol/10mmauto.php

Hodgdons MAX load for 180gr SIE JHP is 5.8gr of HP-38, if you reduce this by 10% your MAX load would be about 5.2gr. starting load would be about 4.7gr. But remember changing any component will give different results (pressures) including seating depth (OAL’s) or primers. With only about .5 of a grain spread from low to high I’d probably load in .1gr increments. OH, and you better check my math just encase.

According to your figures 4.5gr would be your STARTING LOAD not your MAX load if I’m understanding you right.

[joneb]

One could crimp a sized and empty case, and note the inside diameter difference.
When I'm working up a unfamiliar load I start low, I'll load ten rounds, and then ten rnds with + powder and so on, maybe fifty in all. Then off for testing, you can always bring along factory ammo for a supplement.
A new Glock may need to break in with some factory ammo, mild loads may not feed reliably ? I use a lighter recoil spring in my 1911 for mild loads.
patients is your friend

[armedandsafe]

You will get a different crimp on an empty case from what you will with a bullet in place. Crimp a bullet into an empty, unprimed case. Then knock it out with an impact puller. Measure that mouth dimension to get an accurate reading on your crimp.

Pops