Home Forums Reloading Big Game Rifles Small Base Sizer Die...how often necessary?

I've been reloading for years. Never knew about a small base sizer die. I hear they are sometimes needed for pumps and semi-autos. I've recently picked up a Browning BAR MKII in .270 and a Remington Model Six in .270. I've shot the Six a little and it functioned fine. Have not shot the BAR yet.

How often is the small base sizer die needed? Or, does it make sense to use one to avoid possible function issues?

Thanks guys,
Fenton

All depends on how tight the chamber is. I have reloaded for two different Remington Semis. One needed it, the other didn't. Generally though the two you mentioned are most common than other types of actions.Sometimes it is lack of cleaning that gives the problem

They help, or they don't. Depends on where the chamber is tight, not just whether it's tight. A SB die might result in a longer base to datum line dimension. Cuz brass that gets moved more aggressively at the base has to go somewhere.

Tough to predict in advance whether they'll help. Chambers differ, as do brass sources.

Thanks Saddlesore.
How do you recognize the need for the small base sizer? Feeding or extraction issues? I would think extraction?

Actually it’s feeding. If the base isn’t sized enough it will have a bulge that impedes it from chambering properly. The only time I have run into it was on brass that was fired in a semi auto with a sloppy chamber and not sized enough to feed in a bolt gun.

When I bought bulk once fired 5.56 I ran them through a small base die just as a precaution. I felt resistance on very very few.
I later found out I could accomplish the same thing by taking the decapping rod out of a carbide 357 mag die and accomplish the same thing without having to use lube.

Thanks guys.

Sounds like I should just use the same ammo I use in my bolt .270's and be watchful for any function issues with the pump and semi-auto. If any, buy the SB sizer. Correct?

Yes, feeding. Might run into it when trying to size brass that was fired in a full auto machine gun too.

You will l know right away if it won't chamber. Since you will be reloading for two different rifles,you will probably be full length re-iszing brass .Size a half dozen cases and run them thru both rifles before you do any reloading.That will tell you.
Open you chamber, drop a piece of sized brass in and see if the bolt closes easy

I use small base dies for 223’s

Again, great added info and suggestions. Thanks for the education from all.

I would not use a small bass die unless absolutely necessary. If it is necessary then it is if it's not all you're doing is overworking your brass and causing premature failure.
That said I load for several different ARs in 556 & 6.5 Grendel. Never needed a small. So include a mini 14

I do as well on anything that is going into my AR

I’ve got a BAR MK2 and a Rem 7400, both in 270 Win. Standard RCBS dies work fine. No cycling or feeding issues.

I’m on 6-7 loads on Hornady and Remington brass. Sold my RCBS small base 270 dies, as I never used them.

On a side note, neither of those guns like slow burning powder, especially near max pressure. I’ve settled on H4350 or IMR-4064. H4831SC and RL26 at anything above a starting load and you beat up you brass and gun, due to cycle timing issues.

Also keep the chambers clean and dry (no lube).

Again thanks!

Stammster: Thanks for the caution about warm loads. I usually use H4831SC for my .270's. I'll start low for these 2 rifles.

Buddy of mine needs small base dies for two of his 300 Savage rifles. Haven't been able to find him a set. Could trade a standard set for SB set if anyone wants to trade.

Just to be clear, the issue is with the autoloaders (I.e. your BAR). You should be fine in the Model 6 pump using H4831SC like you would with any 270 bolt gun.

Oh gotcha! Good to know. That Model Six and the BAR I’ve never owned before. Looking forward to spending some time with them.

Brass fired in my Win Model 88 (lever ) 243 when resized would not fit my TCR 243 barrel. I ran then into my RCBS trim die first then resized them for them to work in my TCR. Finally bought the SB die to eliminate an extra step.