I was reloading some 30-06 this morning and I realized that my sizer die is a small base die! The box that it came in says that it should be a regular FL sizer die so this is obviously a mix-up from the factory. The problem that I have now is the rifles that i have been reloading for are all bolt action. RCBS warns against using them in this application. I have been using these dies now for over 2 years without incident. I also dont FL size with the die, I back out the die enough that it sizes the neck without bumping back the shoulder. My dilemma is whether or not I should contact RCBS about the issue and get the reg die that I ordered. Sort of goes back the the old saying 'if it ain't broke don't fix it,' so to speak.

What, pray tell, is RCBS' warning about using small base dies for bolt action reloading? I would use them for that without worry.

The "small base" would only come into play if you were running the cases all the way into the die (bumping the die hard against the shellholder). As it is, you are simply neck sizing (or partially full length sizing, depending on how deep you go with the case into the die.) If you are not setting back the shoulder, then it is irrelevant how small the base is if it doesn't get a chance to squeeze the case.

At some point (after a few firings, depending on how much pressure your loads are running) you may need to bump the shoulders back. The small base die might give you a bit of pain doing this since it will take lube on the lower portion of the case and much more pressure on the press handle, but a single FL sizing in the die won't doom the brass.

There is also the chance that your die is the regular die, simply mis-marked. It happens.

No need to fix the non-existent problem.

I alwyas buy, where possible, BOTH regular FL Sizing Die and a Small Base Sizing Die for the centrefire calibres that I shoot.

Now just 270 Winchester and 280 Remington.

I in fact most often will size using the SB Die in preference to the regular FL Die to get rid of the small "ring" that sometimes get left on a case just above the head area with a regular FL Die.

Sizing "all the way" with the die in contact with the shellholder.

Or on ANY "once fired" cases that I might acquire.

My dies are RCBS in both regular FL Die and SB Die.

I have never had any problems with cases sized with the SB Die in my bolt action rifles. OTOH I can also report that they didn't give me any better, or worse, accuracy than standard FL Dies!

I would carry on using them without problem.

I use 223 small base dies all the time in my Ruger bolt action. 1X Range pickup brass I use is mostly fired in semi-auto's and my FL sizer would not size the base small enough for the cases to fully chamber. One pass through the SB sizer and all is well.

I have small base dies, I have neck sizer dies, I have full length sizer dies. I have short dies, I size cases for short chambers, I size cases for long chambers. And, I have forming dies, my favorite bottle neck forming die is the 308 Winchester, next, is the 243 Winchester forming die, after that it goes to belted magnum forming dies, and shell holders, my favorite shell holders have a deck height of .125”. Shell holders with a deck height prevent the bottom .125” of the case head from being sized, beyond that there is the companion tool to the press the feeler gage.

Then there is measuring before and again after, then there is comparator methods and techniques, I believe small base dies are nice, not necessary, If I found small base dies necessary I would post the rational for the necessity of using them, there are not many micrometers I do not have, after that comes datums, I make datums, I collect datums, I purchase datums.

I also have collets for two different lathes, If I wanted to reduce the case head diameter I could simple pull the case up in a collet, but first I would have to chuck the chamber up and run an expander in to the chamber to stretch it out. I know that sounds strange to a few but if my chamber allows the case to expand I apply the ‘leaver policy’, once the case expands to the chamber I apply the leaver policy, I leaver (the case) the way I founder.

Then there are gages like the Wilson case length gage, then there are chamber gages, I took 9 take off barrels to a gun show in Dallas, TX. I priced them at $45.00, still that was not cheap enough, I could cut the chambers off and use the chamber as a chamber gage complete with case head protrusion.

Anyhow, before I made a good case for using small base dies, I would measure the difference between a case that was sized with a full length sizer die and a small base sizer die. I would not use a small base dies because it is the ‘in thing’ to do. Glossy of terms: Small base die. A small base die is a very good full length sizing die. I would assume in the scheme of things some full length sizer dies are full length sizer dies and some full length sizer dies are on the loose side, but, then again, chamber come that way also.

At the range, I noticed a shooter struggling, he was looking for help, I stopped what I was doing, he had new ammo that would chamber and fire, he had new ammo that would not chamber. I suggested returning all the Wolf ammo and get his money back, but that was not all of his problems, his rifle shot excellent groups, finding them (the groups) was another problem.

F. Guffey

quote:

Originally posted by Grumulkin:
What, pray tell, is RCBS' warning about using small base dies for bolt action reloading? I would use them for that without worry.

This is off the Midway website

Notes:

Small base sizer dies are usually required for reloading ammunition to be used in automatic, semi-automatic, pump, slide and some lever-action rifles.

These dies size the case somewhat smaller in diameter and also set the shoulder back slightly more than a Full-Length sizer die to ensure proper functioning in the actions of these rifles.

NOT RECOMMENDED FOR AMMUNITION IN BOLT-ACTION RIFLES

Shell-holder NOT included.

"though the will of the majority is in all cases to prevail, that will to be rightful must be reasonable; that the minority possess their equal rights, which equal law must protect, and to violate would be oppression."

---Thomas Jefferson

I'd call RCBS and tell them just to be on the "sure" side of what die your really have. More then likely they will mail you out a regular full length resizing die. You don't need to be sizing down cases more then necessary as this lessens their useable life. Stonecreek gave a pretty good post.

I have a number of autoloaders, pumps and lever guns and I have never needed a SB die. I have a lot of die sets and zero small base dies. How or when they serve a purpose is an unknown to me. Browning BLRs are supposed to be one of the worst offenders but my rifle works fine with the standard RCBS sizer.
One thing you might investigate is the dimensions of the case after being sized compared to other dies and compared to factory ammo. If you want a case sized small you could try a Lyman die. They are some of the worst offenders in my experience - not because they are too big but because they size the cases excessively small in diameter especially at the shoulder. I got rid of nearly all of my Lyman dies because of excessive sizing force and rims pulled off of some cases.

quote:

Originally posted by thecanadian:

quote:

Originally posted by Grumulkin:
What, pray tell, is RCBS' warning about using small base dies for bolt action reloading? I would use them for that without worry.

This is off the Midway website

Notes:

Small base sizer dies are usually required for reloading ammunition to be used in automatic, semi-automatic, pump, slide and some lever-action rifles.

These dies size the case somewhat smaller in diameter and also set the shoulder back slightly more than a Full-Length sizer die to ensure proper functioning in the actions of these rifles.

NOT RECOMMENDED FOR AMMUNITION IN BOLT-ACTION RIFLES

Shell-holder NOT included.

Small base dies do size the case a bit more than regular dies. This means the brass on the case will be worked more and wear out, i.e., head separations, earlier. Brass will wear out eventually even with a regular full length sizer die just not as fast.

So, if someone asked me if they should buy a small base die for a bolt action rifle, it's not something I would recommend because a regular full length sizer die is better for that application. It's not a safety issue though and, as I stated before, I would use a small base die for any type of firearm without worries.

This is off the Midway website

Notes:

Small base sizer dies are usually required for reloading ammunition to be used in automatic, semi-automatic, pump, slide and some lever-action rifles.

These dies size the case somewhat smaller in diameter and also set the shoulder back slightly more than a Full-Length sizer die to ensure proper functioning in the actions of these rifles.

NOT RECOMMENDED FOR AMMUNITION IN BOLT-ACTION RIFLES

Shell-holder NOT included.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

After MIDWAYUSA has sold everyone a full length sizer die they start over by promoting/selling them a SMALL BASE die. Again, I had two rifles chamber for the 300 Winchester mag. One was a non-Weatherby the other was a Winchester Model 70, the non-Weatherby shot one hole group, the Model 70 shot groups that could only be described as patterns (as in shotgun patterns). Winchester and I had words, I started out as difficult then became impossible, all I wanted was a chamber that fit my dies or Winchester dies that fit Winchester’s chamber.

The ammo was the same for both chambers, sizing the cases for the Model 70 was a work out, cases fired in the non-Weatherby would chamber in the Model 70 and would fit the full length die and chamber in a chamber gage with slight thumb pressure. I have 300 Win mag forming dies, small base dies and various full length sizer dies, and I have collets for two lathes. Point? Once the case formed I prefer to apply the leaver policy, once the shoulder of the case is close to the shoulder of the chamber ‘leaver there’.

OR, I could go with “This is off the Midway website”, I choose to determine the need for a tool, again, I form cases for short chambers, I form cases for long chambers and everything in-between .012” shorter than minimum length/full length sized to +.016” longer than a minimum length sized case.

Once everyone has a SB die the manufactures can start over with short chamber die and long chamber dies. I will be trying to talk reloaders out of purchasing the +/- dies but it is not easy to get past “This is off the Midway website”

F. Guffey

quote:

Originally posted by SR4759:
How or when they serve a purpose is an unknown to me.

The original intent was to size surplus 30-06 brass that had been run through a "belt fed ammo unloading machine" with their overly fat chambers, so that it would fit into "normal" chambers.
The biggest difference is the chamfer at the die mouth, to allow sizing closer to the extraction groove.

quote:

Originally posted by Tailgunner:

quote:

Originally posted by SR4759:
How or when they serve a purpose is an unknown to me.

The original intent was to size surplus 30-06 brass that had been run through a "belt fed ammo unloading machine" with their overly fat chambers, so that it would fit into "normal" chambers.
The biggest difference is the chamfer at the die mouth, to allow sizing closer to the extraction groove.

My original comment was intended to convey that I have never ever seen any practical use for one. I have a large lot (1000) of SL54 brass that was unloaded with a belt fed unloader and that brass has been formed for use in many different Mauser caliber rifles including a Hakim 8x57 autoloader. All of the form & FL dies used for this forming are conventional dies.

quote:

Originally posted by SR4759:

quote:

Originally posted by Tailgunner:

quote:

Originally posted by SR4759:
How or when they serve a purpose is an unknown to me.

The original intent was to size surplus 30-06 brass that had been run through a "belt fed ammo unloading machine" with their overly fat chambers, so that it would fit into "normal" chambers.
The biggest difference is the chamfer at the die mouth, to allow sizing closer to the extraction groove.

My original comment was intended to convey that I have never ever seen any practical use for one. I have a large lot (1000) of SL54 brass that was unloaded with a belt fed unloader and that brass has been formed for use in many different Mauser caliber rifles including a Hakim 8x57 autoloader. All of the form & FL dies used for this forming are conventional dies.

I've never had a use for them and all my semi auto run fine. You don't and can't size down to the extractor groove. That's solid web above the extractor groove. If that's swelled that case is toast in my opinion. It would have to be one hell of a big chamber to not size what needs to be sized.

quote:

I use 223 small base dies all the time in my Ruger bolt action.

My 223 isn't a Ruger but I've used my small base die for auto, bolt and single shot.

quote:

Originally posted by SmokinJ:

quote:

Originally posted by SR4759:

quote:

Originally posted by Tailgunner:

quote:

Originally posted by SR4759:
How or when they serve a purpose is an unknown to me.

The original intent was to size surplus 30-06 brass that had been run through a "belt fed ammo unloading machine" with their overly fat chambers, so that it would fit into "normal" chambers.
The biggest difference is the chamfer at the die mouth, to allow sizing closer to the extraction groove.

My original comment was intended to convey that I have never ever seen any practical use for one. I have a large lot (1000) of SL54 brass that was unloaded with a belt fed unloader and that brass has been formed for use in many different Mauser caliber rifles including a Hakim 8x57 autoloader. All of the form & FL dies used for this forming are conventional dies.

I've never had a use for them and all my semi auto run fine. You don't and can't size down to the extractor groove. That's solid web above the extractor groove. If that's swelled that case is toast in my opinion. It would have to be one hell of a big chamber to not size what needs to be sized.

SJ
RIF (Reading Is Fundamental)
I said CLOSER TO, not down to.

Here is my experience with small base dies over the years; many problems people have had with stuck cases in dies brought to me to un-frig were caused by using small base dies because someone told them they had to use them. I have never owned a set and have owned many semi autos for which I reload and never had any problems. Most of the issues with them are NOT from too large of a base; they are with too long shoulder to base length. Just my experience; if you like them, by all means use them. I never recommend them. BTW, if you are talking about the 1919 Browning machine guns, they don't have big chambers, but they do have adjustable headspace which, if set too long, can cause case separations or fat brass.

small base actually returns the brass to the dimensions of new brass, since their is no ammo specifically designed for semi auto calibers and any factory ammo works in any semi auto rifle. I have all the dies, SB, FL and neck only and I have miked them and for the most part their really is no difference. The early RCBS dies where also stamped with BAR for the specific calibers that the Browning BARs where made in. I have a set with that stamping in 300 win mag.

I use small base dies in 30-06, .308, .223, and .300 Win mag. In my case it has little to do with auto-loaders and everything to do with tight chambered custom barrels. With tight chambers a regular FL or body die doesn't always bring a case down far enough for easy chambering.

The SB .300 Win die gets some extra work, because with the expander stem removed it will massage the bases of hard chambering .257 Weatherby, .270 Weatherby, 7mm Rem Mag and .264 Win Mag without touching the shoulder. If you feel brave it will work on live ammo too, not that I'm endorsing the practice.

I don't get small base dies in autoloaders.

Shot M-1s, AR 10s & 15s, Remingtons, Browning BARs, Merkel SR 1. several R-1s and mostly used various collet dies with no problems. Even a DPMS LR in 300 SAUM with max loads were loaded with neck sizing dies.

IMHO, a semi auto really slams a shell home harder than any other action. Most of them also support the case base better than some popular bolt actions like the M 70 and 03' that have coned barrels.

A solution in search of a problem ?

The action on a semi may close faster but not harder than any other action, I have 6 semi auto rifles and several auto shotguns and their return springs are not near the power I can exert on a pump or bolt.

I would like to see a semi slam a round into the chamber and go into battery with a case shoulder that is out of spec, it is hard with a bolt but you can get it to close with some force. That is why there is small base dies to facilitate the the lock up.

Okay but I don't use them, never have, never will and have been shooting centerfire semi autos for 50+ years. Guns and ammo are clean and "on spec" and always work.

Oversizing any brass will lead to premature head separtion.

If what your using is dependable and you are satisfied I agree.
In all my years of shooting I have only had one malfunction with my semi, it was a failure to extract a 30-06 case from a 742, seems it ripped off the rim probably as a result of either a dirty case, dirty chamber , excessive pressure or defect in the case or a case that may have been used once to many times
for hunting rounds irregardless of the action I cycle the rounds to insure all is good

http://www.saami.org/PubResour...06%20Springfield.pdf

I will start off with assuming, first, no one reads and or is familiar with the drawings of SAAMI for case and or chambers. Second the case head drawings indicate the case head rim is larger in diameter than the case head in front of the extractor by .003” (+/- very little).

Then I will assume no one has a chamber gage, it is nothing for me to cut the chamber off of a barrel for a instant chamber gage or, with 100+ plus barrels, it takes no time to use a take off barrel as a chamber gage. And cases, there is no shortage of cases around here, with a chamber gage/take off barrel and 1,000 ++ cases to choose from I can determine the diameter of the chamber to determine if a small base die is necessary. In the most primitive methods I turn the case around and then insert it into the chamber, no surprise to me, the case head enters the chamber as much as .220”, considering most case heads have a case head thickness from the head of the case to the bottom of the cup ‘and not forgetting’ the case head rim is .004” larger than the case body ahead of the case head, and, the chamber measures .470” .200” ahead of the bolt face.

I did not say I do not have small base dies, I said I do not use them, then there is forgotten in time, the M1 Garand chamber had additional clearance by designed, the M1 used the same ammo as the 03, 03A3 and the M1917 etc. the additional clearance built into the M1 was said to be .00023”, then I am told the old folks could not hold those tolerances. Long after that I purchased a Pratt and Whitney electronic gage that was calibrated to .000005”, the 35 lb. gage was of little use to me so I removed the electronics and replaced the electronics with a dial indicator that reads .0001”.

Back to cases, my Remington R-P brass has a case head thickness of .260”, my military, with the exception of Winchester, has a case head thickness of .200”. then there is the shell holder with a deck height of .125”

Small base dies, I know I have 270 Winchester, 30/06, 300 Winchester mag and 223, do I need small base dies? I can measure case head diameters, I can measure the diameter of a case head sized by standard dies, I can measure the diameter of cases sized with small base dies, Finding a difference in the two cases is not easy, or, I have some very good full length sizing dies.

As always there is sizing cases for short chambers.

Then there are reloaders that go through the motion of sizing a case with no clue if the case was in fact sized to minimum length when the ram was raised. When a case whips my press I know it, when the case has more resistance to sizing than my press can overcome, I know it.

F. Guffey

I always purchase small base dies and full length resize in many chamberings. I like the fact that the case is minimum size and feeds better. In 30-06, I use small base exclusively, but then I have 2 levers, a pump, an autoloader and a bolt gun in 30-06. I've been using the RCBS small base set for 36 years with zero issues!

I have loaded for half a dozen semiauto rifles and never thought a small base die necessary until the Garand. I had numerous closed bolt slam fires with full length sized reloads; since I started using a small base die, I've had nary a one.

quote:

Originally posted by Grumulkin:
I have loaded for half a dozen semiauto rifles and never thought a small base die necessary until the Garand. I had numerous closed bolt slam fires with full length sized reloads; since I started using a small base die, I've had nary a one.

I would be interested in reading more on the slamfires. What type of primer were you using and did you use case gages to set up your dies?

I am 100% pro small base dies, I set them up with Wilson gages, set the shoulders back 0.003 or size to gage minimum. I can use that ammunition in any of my rifles in that caliber because they all meet factory headspace.

I get exceptional case life, took one set of LC66 24 firings and 23 reloads in a M1a. Most of the time these cases were small base sized. I did however, lubricate the cases and fired them that way so they would not develop case head separations. I quit using them when the pockets got large.

In the aforementioned Garand, I never had a slam fire with CMP ammo; just with reloads with full length sized cases. I did not use a case length gauge to set up the die. Primers were CCI #34.

I contacted the firm that had rebuilt the Garand to like new specifications and they were unable to get any slam fires (or doubling as they preferred to call it) when I sent the gun to them for evaluation. Prior to the small base die, out of an 8 round clip, I would usually get 1 or 2 slam fires. Since the small base die, I've run probably 150 rounds through it with nary a one.

I've shot hundreds of full length sized reloads using Federal 210M primers in a National Match M1A and never had a problem. Ditto in AR-15s and others.

So, I believe that in most instances, a small base die isn't needed but that there are special cases in which it is needed.

This is a reloading forum, I am a reloader, if after sizing a case it will not chamber I want to know why, before reloading for a chamber I know the dimensions of the chamber, I know the length of the chamber from the datum/shoulder back to the bolt face. After sizing a case I can measure the length of a case from the datum/shoulder to the case head with home made tools. I know if the case will chamber before I attempt closing the bolt. Meaning, if a small base die was required I have small base dies.

Short chambers, I ream chamber with short chambers, I form cases for short chambers, when keeping up with ‘where I am’ when reaming a chamber I use short cases. Someone else tells me I ‘must check often’ to determine how close the chamber is to being finished. And, they have no clue what I am talking about when I say “If I wanted to know how close I was to finishing the chamber I would use a go-gage” or a minimum length/full length sized case.

I do not sell small base dies, if a small base die is necessary ???? still I do not need a small base die, again, I form cases for short chambers. But if I did need a small base die I would know that was the only option.

F. Guffey

I don't KNOW if there's a spec change for machine gun chambers but I really doubt it, no matter how often it crops on web posts.
SAAMI has standard dimensions for both chambers and ammo, the largest ammo is always smaller than the smallest chamber to prevent jamming into the chamber.

Standard loading dies match the ammo so it's higjhly unlikely a PROPERLY resized case loaded cartridge won't chamber; I've been doing this a very long time and I've never seen any problem chambering properly made reloads in a clean chamber of any rifle.

SB dies are only about 2 thou smaller in the lower case body and that's mostly so the ammo will fit in a grimy chamber. I've never observed overly grungy chambers in a bolt rifle.

I'm not a weight lifter but I've never had a properly lubed case fail to enter a sizer quite easily. And the lightest of my presses have no trouble sizing anything I've ever fed them.

Jim C. <><
one of us
posted 14 April 2013 06:3214 April 2013 06:32 Hide Post
I don't KNOW if there's a spec change for machine gun chambers but I really doubt it, no matter how often it crops on web posts.
SAAMI has standard dimensions for both chambers and ammo, the largest ammo is always smaller than the smallest chamber to prevent jamming into the chamber.

-----------------------------------------------

Jim C. <><, Machine gun chamber? I claim the M1 chamber, in the beginning, was different, the difference had nothing to do with chambering, it was all about ease of extraction, then I am told there is no way tolerances could be held to the close tolerances claimed, and I said “Fantastic”. Anyhow, the two chambers, as in M1 and the 03/ M1917 were published, in a few places the drawings were printed on the same page for comparison.

Then the part about tolerances, I have an electronic gage with a Pratt &Whitney Plate riveted to it, the gage read .000006, useless to me, I removed the electronics then attached a dial indicator to the stylist, back to useful, it weighs 35 lbs. Point?

Again, I have small base dies, when comparing cases sized with standard dies with small base dies it would be easy to compare the difference if the difference was .002”, it is possible a reloader could have some very good full length sizer dies. For those thought to size cases I have forming dies.

I had words with Winchester over a their chamber, I wanted a chamber that matches my dies or I wanted Winchester dies to fit their chamber, long story. Their remedy, hone, polish or ream?? I could not think of a way honing, polishing and or reaming could reduce the size of the chamber. BUT! First, I had to shoot the rifle more.

F. Guffey

I was able to get my hands on about 5K of 5.56/223 cases that had come from a security force training range. There was no way I was going to take my chances with that many cases out of that many different rifles, expecting to not have a problem. One trip through the SB .223 dies and I have yet to have a problem in any of my ARs.

Just a chance I was not willing to take. You guys can do what you will; I will use SB dies for handloading .223/5.56 and 6 X 45 as long as I am using "1X fired range brass"...

I managed to wrangle about 100K off the National Guard Armory that's equally been through many different firearms and I sized them with regular Redding 223 dies and have had nary a problem in my AR's nor in my 6x45 wildcat AR's. Very few circumstances does one need SB dies.