MV is all over the place..

[coach4christ]

need some help guys. My SD was 22 when checked today. Need some pointers to help out. My reloading process is as follows.
1. Trim
2. Decap/neck size collet die
3. Tumble ss media
4. Chamfer/deburr
5. CCI Br2 primer
6. 42 g H4350. Load to 41.5 and trickle to 42 on a chargemaster
7. Seat with Forster competition die.
Thanks for the help..

 

[spife7980]

Just curious, is this the first time you've checked it or has it gone from good prior and now to bad?

 

[trophyhunter]

What he said ^^
But also I've noticed I get better spreads with 210m primers. It brings speeds a tad slower in my calibers I shoot but I've noticed my SD's are more consistent and lower. And I have less issue with primer flowing.


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[shoot4fun]

Hmmm. Since SD is not several numbers but instead one number derived by a complex calculation of each velocity number in the string I would say your SD is not "all over the place" but your shot to shot velocity has quite a variation to it.
I wonder too if you have checked it many times before and saw much lower? If so, maybe you changed brass(new lot or brand), powder lot or even primer lot? Many factors involved in lowering SD. These would be the first one I would look at.

 

[coach4christ]

First time to check. I borrowed a buddies magnetospeed this morning. When doing load development, I usually find the bust groups at 500 yards and use that. I always assumed that I had pretty consistent mv, but dang, this morning it was all over the place. I am using hornady brass, lee collet die, cci br2 primers. I try to be meticulous in my prep and loading.

 

[Kadams1563]

How many firings on the brass?

Have you annealed the brass?

I found that my reloads used to be single digits and when I tested the other day after 4 firings (not annealed) they were creeping up to the 20's.

I do things differently then you though.

I deprime with universal decapping die.
Tumble in SS
Lube and resize
Trim
Prime
Powder
Seat Bullet with imperial dry lube on Bullet.



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[coach4christ]

6-7 firings, yes I anneal every 3 firings.