Small Base Dies Needed

[Bassaro]

Hey guys figured I'd share a experience with you and see if anybody else encountered it or if it's just me. I have been reloading for a while for a variety of calibers. I have always believed small base were just another marketing gimmick...actually I was a firm outspoken believer of it...till I started reloading for my M&P 10. I am a RCBS fan, I have tried all the others brand of dies from old Herter dies to Lee, and have always used the green boxed regular based dies for all my semi auto and bolt gun reloading. When I got my m&p I grabbed some factory privi I had and ran to the range. After wasting the majority of that ammo figuring out the whole to small gas port short stroke thing I finally had her running and ready for load development, only to find that every other round would get stuck in the chamber and I would have to pogo the bejesus out of the gun to extract said round. Tried a variety of bullet seat depths, set the shoulders back further, tried a factory chrimp die, all with the same result.

So I broke down put my foot square in my mouth and bought some small base 308 dies. And wouldn't you know it problem solved. She runs like a champ now and I am very happy.

I have been reloading for semi autos for a while now, all my 223s work just fine with the standard green box dies. My fal ran just fine as well as a buddy's DPMS 308 I loaded for using the green box dies.

Have any others ran into the need for small base dies?

 

[Waywatcher]

Never tried it any other way. RCBS said small base dies for my AR, so that's what I bought--I tend to follow instructions, especially while reloading. Never a problem here. Doesn't seem like a marketing gimmick at all if one is starting from scratch, like I did; just the proper equipment.

Glad you got yours figured out!

 

[Bassaro]

When you haven't started from scratch you are amazed when you see it play out.

Like I said I have used standard dies on other semi auto 308s even AR variants. If anyone plans on loading for a M&P 10 and doesn't already have 308 dies, to try to see if their experience is any different from mine, play it safe and get small base dies.

 

[obgjedi]

I too bought the small base dies since this was my first AR reloading experiance and I have not had any problems. getting some 1 moa groups and I am very pleased with the M&P 10

 

[copemech]

Considering some reloading myself but must drag out old gear. I have die set, what is the difference and what loads are you running if folk do not mind sharing?

 

[Bassaro]

IMR 4064 is my go to powder for all things 308. I hear the heavier bullets run the best out of the M&P barrel, looking in the 165-180gr range. I personally have a big supply of military pulled bullets in 147gr so I haven't tried the heavier bullets but I hear they are the ticket.

 

[GLKmiester]

How does this translate to Hornady dies?

 

[Bassaro]

Even Hornady makes a small base die set, it's not a RCBS exclusive thing. Your die box will be labeled somewhere if they are small base dies. If they are not labeled anywhere and have been working fine for you then post it up, I'm curious.

 

[copemech]

What is different with small base ?

 

[Richard Hoops]

I would like to know the difference as well.Can some one answer this?

 

[Brianengy]

Same as FL but have a smaller base. Better for auto's.

 

[Waywatcher]

What is different with small base ?

Small base dies resize the base of the brass, near the head, slightly smaller than full length dies.

Bolt actions have enough leverage to force fit a tight base, while most automatics, lever actions, or pump actions do not--meaning these actions benefit from a small base die.

In reality, it's more reasonable to consider standard full length dies as being for "bolt actions only," as small base dies are best for pretty much any other kind of rifle action.

 

[MichiganScott]

I find the recommendations in this thread for small base dies interesting. Although I do not own an AR10, I've owned and reloaded for several AR15, M1, and M1A rifles and never found it necessary to use small base dies. Military rifles tend to have chambers on the large end.

The Remington 740 rifle is the only one I've ever found SB dies needed. I've never needed them for several M99 Savage or Winchester Model 94 either.

 

[webfarmer]

I agree with the others having never used small base dies for my M&P 10, AR15's and M1 Garand. Never had a problem although I haven't had a chance to run the .308 much yet (c'mon spring). From what I've seen in forums, small base dies may work brass faster (less reloads) but I have no experience with that. Either way you go, just be sure the shoulder is set back correctly using a Wilson headspace gauge and trimmed to length. Good luck!

 

[tlshores]

I am a new M&P 10 owner and not well schooled in this particular model.
What exactly does "The whole small gas port short stroke thing" mean ?

 

[Bassaro]

I am a new M&P 10 owner and not well schooled in this particular model.
What exactly does "The whole small gas port short stroke thing" mean ?

Short stroking is when you fire a round and your bolt does not go far enough back to pick the next round up out of the magazine to chamber it. You will see several threads started all the time on here as this rifle is notorious for short stroking. S&W for some reason drilled several of the gas ports to small on the barrels, thus not allowing enough gas into the rifle to properly cycle it. The solution is to send it back to smith (and wait 6 weeks in hopes that they drill the gas port bigger) or go to a qualified gunsmith and have your gas port opened up slightly.