.223 small base dies?

[Yurko]

I saw this term on another thread & didn't want to hijack that thread so I'll start a new one.

What is meant by "small-base dies"???

thanks!

 

[n4zov]

Generally speaking, when ammunition is fired in semi and fully auto (and some other action type) rifles, the lower part of the case tends to expand more than it would in a bolt action rifle. Small base dies are made with somewhat smaller dimensions in that area so they will reduce the case to near factory dimensions and allow the case to be used in the same type rifle. Bolt action rifles have more camming power than other action types and therefore can handle greater variations in case dimensions. I strongly suggest NOT buying small base dies until you are sure you need them. I have never needed small base dies for cases fired in M1's, M14's, AR-15's, or Mini 30's. However others may have had different experiences.

 

[k22fan]

Small base dies are usually purchased to resize brass small enough for reliable functioning in simi-autos, pumps or other guns that do not have the camming leverage of bolt actions. Most FL resizers are not made as small as SB FL resizers because too many people do not take the time to adjust FL dies to their individual chamber and for them a SB FL sizer increases the risk of dangerous excess headspace.

For safety, die manufactures have to keep FL sizers near the large end of the tolerance range even though they know they are selling FL dies that will not make brass small enough for all the chambers they could wind up being used for. Three or four times I have had RCBS FL dies that would not resize cases small enough to work in my rifles including one SB FL resizer that did not work with an AR-15 based target rifle. Each time I sent the die back to RCBS along with fired cases and RCBS happily made a die custom fitted to my chamber for free. That may be a better alternative to buying a SB FL resizer.

Best regards;

Gil

Post Script: I see n4zov got a good reply posted faster than me. I agree with every thing he wrote.

 

[Joed49]

A few years ago I reloaded ammo for a friends AR. I was perplexed that the rounds wouldn't enter his chamber. It was at this time I learned about the SB dies. Using these dies all rounds fit his chamber.

 

[Dragon88]

Small base dies work very well for some rifles. However, they are a solution to a problem you may not have. Regular FL dies will work the brass less and extend case life, so only go to the SB dies if you have chambering problems.

 

[Yurko]

Thanks for the edumacation!

My AR does quite well with my reloads, so need for the sb dies.
I was just wondering what they were.

 

[mgjohn]

Small base die are useful when you are reloading brass that has been shot in a unknown gun(s).

IE: range pickup brass, of brass that has been shot in a diffrent type of gun than yours. For example sometimes brass shot in a Mini 14 needs to be SB sized to work properly in AR type of guns. Or brass that is shot in a 16 needs to be SB sized to work properly in a bolt gun.

 

[n4zov]

Small base die are useful when you are reloading brass that has been shot in a unknown gun(s).

IE: range pickup brass, of brass that has been shot in a diffrent type of gun than yours. For example sometimes brass shot in a Mini 14 needs to be SB sized to work properly in AR type of guns. Or brass that is shot in a 16 needs to be SB sized to work properly in a bolt gun.

That's a good point and it particularly applies to brass that has been fired through full auto weapons. Military brass picked up off a machine gun range would be another good example.

 

[kscardsfan]

I've only heard of a few situations where people HAD to use SB dies. And naturally, they were all in AR type rifles. I asked my gunsmith when I just bought my AR and my M1A if I needed SB dies since I was new to both these rifles and bottle necked/rifle cartridge reloading, and his advice was to use my full length dies until I knew for a fact I couldn't use them and only then start looking at a small base die set. So far haven't needed them yet. Maybe I just have sloppy chambers

 

[mr. bob]

And there was the hombre that small base dies would not work, two different sets, but the RCBS small base X dies solved the problem. The ar was a Bushmaster, shoots 5shot in 3/4 if I do my part. The very best to all of you.

 

[safarihunter]

I picked up a set of used small base dies when they were available at a great price. I bought them for "just in case".

They have come in handy on several occasions.