rcbs black case

[ewmn]

I am getting ready to start reloading for my m&p 10. So I have been reading up on the subject. I see a lot of talk about small base dies and it seemed to me that sb is the way to go. So I got a set of green box rcbs sb dies. This was my first set of rcbs dies and I had a question about cleaning the dies before first use. I called rcbs and the rep. told me the proper steps for cleaning the dies. Then he ask me what rifle I was reloading for. I told him a m&p ar 10. He said the green box s/b dies would probably be ok but recommended the ar group black box set and said they were designed for ar rifles. I took the green box back to the store and now I have a black box. Tag on the black box reads 308 win sb t/c die set p/n 15507 group:ar Is anyone using these dies ?

 

[Bat Guano]

Well, I've been running SB die rounds in my M1A for a long time, and the loaded ammo I had on hand works fine in my 10. I don't think SB dies would be particularly critical, but they're going to chamber up a bit more freely. There's no real drawback to using the SB dies other than possible reduced case life. Personally I have not found that to be an issue.

What I do think matters is to monitor case length and headspace as sized. Both are liable to change upon firing; variations in those may not create much trouble in bolt guns, but semi autos want good consistent,in-spec ammo.

I size and trim all my 7.62 brass with a Dillon trimmer, check all the processed brass in a step-type case gauge, and check those same items on each finished round.

All of which takes some time, but it's worth it.

 

[bergermeister]

Have NOT found SB sizing dies necessary in a MP-10. Why overwork your brass if it is not necessary?

 

[webfarmer]

Berger, I don't know about that. Doesn't your 10 rough up the heads during ejection enough that you have to file or pitch cases? Mine is really hard on brass. So it makes me wonder if SB is really all that bad considering - on the M&P 10 only. I have used regular dies on my 5.56 brass with zero problems. Never a need for SB on the 15. The 10? Not sure why it's so different.

OP - didn't answer your question but you should know - the M&P 10 IS NOT an AR 10. They are two different rifles. I suggest sticking to the OAL from whatever bullet manufacturer you choose until you get some shots down range. The Smiths's seem to be picky about that (mine anyway). Good luck and have fun!

 

[2cants]

I use the black AR10 series dies.

check my handload thread.

http://smith-wessonforum.com/smith-...48-my-mp10-good-load-max-168-39-5-varget.html

I'm consistently getting around 1" @ 100m now. I notice that mr MP10 liked a bit of crimp. Goodluck.

 

[MasterTech1960]

I also use the AR series in the black box for both the 10 and the 15. Have not had any issues with either . I also use the Lee factory crimp dies for both. Shooting sub-moa with both guns with certain loads.

 

[ewmn]

Bat, I couldn't agree more about case length/headspace. I have a wilson gauge on the way along with a new rcbs case trimmer. Thanks amazon. Is a matter of fact I'm sitting on 500 1 fired lc cases and I won't size 1 of em til that wilson gets here.

 

[Bassaro]

I had to get small base dies to get my M&P 10 to run. I have reloaded for several 308s with my green box dies but had to pogo about every round when using the green box dies.

As far as working the brass to much let's not forget we are running a semi auto chances are you will loose the brass before it cracks on you.

If you don't have a set of dies already just play it safe and get small base dies.