I picked up a few bags of LC once fired brass. I guess its machine gun brass? Anyway. I have never had a problem with other brass and loadings chambering. But I picked up this LC and was told to use a small base resizing die. I bought an RCBS and used it. Last night I processed a ton of this stuff, loaded up a few 168's and tried to chamber a couple of them and they wouldn't go into battery. In fact, I had to beat the charging handle to unstick them. What's up? What did I do wrong? I hope I didn't screw up using that small base resizing die.

always use a case gauge, chamber the first resized cases to insure fit in your specific rifles and spot check with gauge as you are sizing. Correct prep is the foundation that has to be correct.  I hate prepping machine-gun brass.  It is worth it to me to buy bolt fired stuff whenever possible.  you also need to gauge and chamber the first complete rounds to make sure your completion of the round didn't change the geometry.

Most likely you don't have the shoulder set back far enough, i.e. the shoulder to base distance is too long which won't allow the case to chamber.  Did you check them in a case gauge?  Both ends?  Setting the OAL of the brass is meaningless in a necked rifle cartridge because the shoulder is what the case indexes off of, not the OAL.  So, first you have to set the shoulder to base length and then you trim the neck to the correct OAL.

If the shoulder is correct per the case gauge, then I'd take a sized and trimmed empty case and try to chamber it.  If it doesn't chamber either you have a short chamber and the shoulder needs to come back a bit more or a short lead and you need to trim the neck a bit shorter.  If it does, then measure your empty case neck diameter vs one of your handloaded rds and then compare those to a commercial .223/5.56 .308/7.62x51 loaded rd to see if maybe the bullets are malformed and over size.

168 gr bullet implies .30 caliber cartridge, correct?  
Based on the 'machine gun' comment, let's assume then a 308 and not 30-06.  Is that correct?
'Beating on the charging handle' means it is an AR10 rifle, correct?

What lube are you using?  
What dies, a small base RCBS and what else?  
What gage are you using to set up the sizing die or did you just have the die touch the shell plate?  
What barrel/chamber are you trying to fit into?

Buy a Sheridan case gauge.  Do it. 

In the interim, you can take a large magic marker, ink up the case, chamber it, and then remove and inspect. 

I use Forster dies with LC brass all the time. I have about three  .308 chambers they all fit in.  

The Wilson case gauge would not identify the issues that a Sheridan will. Sheridan Engineering

You're right!  I read it fast and thought he said 68grn, not 168grn.

Yes, 308win. and yes AR-10.

I'm using Lee water based lube
I used the RCBS die for resizing and Lee dies for the rest.
I just had the die touch the shell plate, no gage.

Assuming the lube is properly applied, you should be okay.

Sizing die should be screwed down in small increments until cases chamber with ease.  After a time or two, you may need to relube that case.

Perhaps 1/8 turn down, size, test in chamber.  You will encounter resistance when you size.  Just press through the resistance and you will feel the press 'cam-over' ('pop' thru the resistance).  This takes out all the slop in the linkage and allows you to apply a little more force to the case going into the die.

Honestly, with the 'cam-over' technique you could have used the original die but the small base will also work.
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Do yourself a favor, buy a tin of Imperial Sizing Die Wax and/or buy Dillon Spray Lube.  These are clearly superior to everything else.

Do yourself another favor, buy a Hornady gage set (headspace and OAL).  This gage is better than a case gage.

This!

The case gauge is simple and easy to use. I love the Hornady comparitor. I have several different comparitors from different companies, but they are still just comparitors. If one is sizing strange brass for use in self loading rifles the case gauge is the way to go.  The gauge will let you know if the case meets specs or not.

I do agree with TrollSlayer's advice with respect to press, die, and lube usage. I just think for your purpose and experience you'd be better served by a good case gauge.

"Touching" the shell holder may not be enough. When the press is under load the clearance in all of the links can and do add up to a surprising amount.

Go back to the SB die and adjust it down to firm contact under load or to cam over if your press will cam over. You may want to do the same with the Lee full length die as well.

Motor

I put a Sheridan slotted gauge on order.

I am still new to reloading, but have never encountered this. I have reloaded a ton of .308 with my Lee press and have never had a problem with any brass I have used.

Here is my question and please be patient. But how do you adjust the resizing die to push the shoulder back? I have always used my Lee die right out of the box. I am using the RCBS small base die.

The sizing die will push the shoulder back a bit as the case enters the die.  How deeply the case goes into the die determines how far back the shoulder gets pushed.

Right now, it seems likely you are limited by the base of the case (machine gun ammo).  Don't worry about the shoulder.  You need to compress the bases of the cases to allow them to fit your chamber.  Once you get all that done, all your cases will fit your chamber with ease.  This deep sizing should be a one-time thing.  All subsequent sizings will be of cases that fit and were fired in your rifle(s).

So, size them as much as needed and fire them in your rifle(s).

After that, you can begin to think about how far back the shoulder should be pushed.  This will almost certainly require a re-adjustment of your sizing die but once it has been re-tuned you will not likely have to worry about it for a long time (or ever again).

I had this problem with mixed brass, some LC included.

Using a Dillon FL resizing die, I had to crank the die down farther than I originally suspected I needed to.

I had cases that were fine in the case gauge but sticky in the chamber.   I actually modified a second (slightly damaged) Dillon FL resizing die
for the specific purpose of resizing loaded rounds.  I got things sorted out and have actually chamber checked every single round, in an upper
separated from the lower.

Get yourself a box of Winchester white box Q3131A and use that as a sizing reference.  It's guaranteed good to go and will chamber properly.
Use it as a reference and your reloads should chamber just as easily as the Winchester does.

I am using a small base die. How can I get the bases even smaller?

By pushing the case farther into the die, the die will reduce the outer diameter of the case allowing it to fit into the chamber without binding.

After sizing, be sure you check the case lengths and trim as needed to maintain the proper length.

I decided to experiment a little. I loaded 5 rounds using the same brass and same bullets, but ran the brass (that had already been resized in the RCBS die) through my Lee resizing die instead of the RCBS small base die. I was able to chamber 4 out of 5. Should I just run all this brass through my Lee die and maybe turn the die down a little?

I have also measured everything on the resized brass and everything looks spec.

UPDATE: I remeasured the case length on the 5 i reloaded. The 4 that chambered were at about 2.012. The 1 that didn't chamber was at 2.032 (although it "kinda" chambered the 3rd time). And yes all the other cases are about 2.005- 2.010. The one that is 2.032 probably stretched a little from being run through the Lee die. That's my guess anyway

I know how to do it. I've done it a few times, thankfully not a lot. It just didn't work. They were stuck stuck. Of course having a milspec charging handle doesn't do you any favors.

You are discovering what everyone else has when dealing with once fired surplus 7.62x51mm brass. It's tough to resize and military chambers are much larger than commercial .308.

I never needed small base dies, but I have to turn the 1/8 or more past touching the shell holder to get the shoulder bumped enough. I no longer use or recommend drop in case gages. They simply are inferior to Mo DeFina&s, RCBS and Hornady Lock-N-Load.

You need more lube non the case body and none on the case shoulder. I run the brass hard into the die and let it stay inside while I lube the next case. Even though they are once fired I trim every one to 2.000".

On rare occasions I sometimes need to run the brass through twice to get the desired clearance. This brass used to be cheap and plentiful, now it's not. I prefer to purchase IMI brass in bulk to avoid the headache of dealing with Lake City. It's not the brass that's to blame, it's the G I chamber specs that cause these issues.

When you prepped the once fired cases, did you trim all the cases after sizing? If not, that may be the issue.

Here's my once fired LC case prep steps:

Decap, remove primer crimp, primer pocket uniform, flash hole debur, wet tumble case, lube, FL size, trim, chamfer (inside/outside), tumble to remove lube. Only the flash hole debur and primer pocket uniform is optional.

Your shoulder is the issue. A small base die is not required to size brass ran through a MG. It’s all about getting the shoulder set back far enough.

Shoulders would stop the case from chambering but is less likely to require mortaring or hammering to get the round back out.  IME, that is caused when the base of the case wedges into the chamber.  Still, you could be right.

Does OP have a pic or can OP describe what part of case is causing the wedging?  It should show scuff marks.

I had a similar issue with .223/5.56. I could not get the die far enough down even with cam over to push the shoulder back(i did not know this for sure at the time). About 1 out of 20 would stick itself. Unlike you I have a gauge for every caliber. Every round I ever reload goes into a gauge. They all fit(well after I figured it out there was a miniscule diference in the ones that work and those that stuck). I too bought small based dies. I too stuck brass in them the first time until I got imperial sizing wax. I too did not solve the problem with small base dies. At this point I got pretty pissed.

I then decided to use my problem solving skills. I bought an RCBS precision Mic, which measures the case from the datum point on the case shoulder back to the case head. I put a factory piece of loaded ammo in it and measured, IIRC it was a couple thousandths under spec. Like -3 or so. Then I put in an unsized fired case(when I say case I did it like 30 times), it was around 6-8 thousandths over spec. I then resized that case and this time it measured 5 tho over so barely any push on the shoulder, which was nowhere close to the -2 or -3 of the factory round. I tried screwing the die down till I thought I might break the press. Measure again still +5.  There was no way in hell that die was going to size that case into spec. I tried a few more, some did push the shoulder into the +1 to +2 range and that was enough to make them chamber but not to exact SAAMI according to,the gauge and not even close to factory. So now what? Well I realized that in order to get the shoulder back i had to get the case further up in the die so either I somehow machine the shellplate thinner so the die can go further down or I file the die base. I filed the die down a little, put the die back in all the way to cam over. Run the same case through, bam -6... back the die off to hit -2 consistently. Problem solved. Now filing the die is a bit on the extreme side and I would exhaust everything else first and probably have someone machine it instead of going full Bubba style but I was so mad at that point. Problem is solved. anyway here are my suggestions to try as I ran across a lot of ideas as I was figuring this out.

1) just use non military brass that works.

2) take a sized case that doesnt fit the chamber after sizing, and size it again but this time remove the decapping rod with the expander ball. Ive read sometimes the expander can be a little large and on the up stroke strech the case shoulder. After removing and resizing see if it fits. If it does try sanding down the expander ball a little at a time and see if you can solve the problem that way.

3) if you arent sure the problem is with the sizing die and you are using any crimp, adjust the die to take all the crimping off. Ive seen collapsed necks cause an issue as well. Crimping on mixed headstamp brass can vary the crimp case to case.

4) get a tool that will help you identify and quantify the problem, RCBS precision mic was invaluable for me to solve the issue because I could see 1) the problem 2)the amount it was off 3) how far off factory was good,enough and 4) what result my trying things had on the problem. Possibly your gauge you just ordered will be enough to see I dont have experience with those so I dont know. Either way you need a gauge, not only do they make sure things fit but when things dont fit it can be case defects causing it it helps catch mangled rims and sometimes cracks or an impending case head separation you may have missed.

I don't know how it got to 2.032 but that's scary. Proper trim length is a MAJOR safety concern. If for some reason your case length is long enough to be jammed into the start of the rifling this effectively crimps the case mouth down tight onto the bullet and does not allow it to open to release the bullet.

This situation can easily destroy your rifle as well as yourself and anyone unfortunate enough to be near you.

I still say firm contact with the shell holder or cam over if your press will is going to solve your fit issue. As you already stated you may not even need the SB die but it still shouldn't hurt to use it.

Your case length growth as well as the amount of growth is directly related to the amount of size change that each case went through. The small base die on average should cause more length growth because it as the name implies sizes the base smaller.

As you reduce the diameter of the body the case grows in length mostly between the web and the shoulder but then the shoulder hits the die and is pushed back. When this occurs the brass "runs" up the neck because that's the only place it can go making the case OAL grow.

Of course if you are trimming away brass that brass had to come from somewhere and that somewhere when it comes to .308/7.62x51 casings is right where the web/body meet. This is true for most rimless casings I say most because for some weird reason it's a little farther up the body on .223/5.56 brass.

This is why probably more than 90% of the people on this forum will say using SB dies when they are not needed does nothing but shorten case life because  the extra sizing leads directly to more growth which directly leads to more thinning at the web which leads to cracking and or head separation.

Personally I've never had any fit issues with LC or any other military 7.62x51 brass. I use standard RCBS full length die and full cam over on my Rockchucker II press. I have definitely noticed needing extra force to do some of this brass and I always closely monitor the "feel" and can tell when to back off and re-lube then try again.

Within the last year or so I switched all of my 7.62x51 for semiautomatic use as well as my 30-06 for use in the Garand over to RCBS X-DIES. So far this is working just as advertised. I haven't needed to trim any of them after the first time.

Motor

Thanks for all the help. Honestly, I have never had a problem with commercial brass. Even ZQI brass has been awesome for me. But most of my commercial brass was first fired in my gun. Even brass that I've picked up at the range was probably fired out of bolt guns or other AR-10's. But this problem with this military brass has shown me that I need to be more careful about my reloading. I don't consider myself reckless, but maybe I'm not as careful as I should be. I have a slotted case gauge coming and will start using that when I do .308 regardless of where I got the brass.

But all that said, I am a reloader mainly for economic reasons. I have a good amount of steel case ammo stashed away in case of an emergency, but I don't shoot much of it it out of my AR's. (I give that crap to my AK, it will eat anything). By reloading I can shoot brass for what I pay for steel. It does take time, but its also kind of a recreational thing for me. I turn on an oldies station and have some me time. I have always used my cheap Lee single stage press. I could probably get better results out of better equipment, but it works for what i do.

Anyway, thanks somuch for all the advice and being patient with me. No matter how much I learn, I discover there always more to know.

The die is still sizing that part of the case even if you never bump the shoulder at all.  More than likely his shoulder spec is a tad too long but allowing for a partial lock of the lugs.  On a bolt gun with the same round this will equate to a hard bolt close/open if the case isn't sized enough.  It's enough to lock up an auto pretty tight.

I had the same problem with once fired 7.62LC.  Die all the way down still wasn't enough.  Chucked my RCBS small base die in a lathe and took 6 thou off the bottom.  Problem solved.

Use a gauge?  I use, something like this.....

https://www.midwayusa.com/product/1016251573/le-wilson-case-length-headspace-gauge

Do you get "cam over" when you resize your brass?

Story time.

My reloaded .308 Win ammo would fit my M1a easily. But, when I tried the same ammo in my bolt action Rem 700 (.308 Win)....well, it didn't chamber. Humm.....ok, so I screwed down the re-sizing die down a bit more. The new ammo is just passing, in the gauge test. Remember, there is a high and a low cut, to test for re-sized brass to still be acceptable. Now, the ammo would work in both rifles.

Bottom line: chambers vary and a little bit could be all the difference.

BTW.....I'd say that the largest proportion on 7.62 surplus LC brass is/was more than likely shot out of MGs.  Think about it......once the M16 became the standard, what's left?  So, back in the old days (since the 70s).....the 7.62 Nato brass probably came out of the M60 (today, it's from the M240).  I have a lot of brass from that 70's era.  And, the chambers in the M60s were "generous."  I use to have a hard time with re-sizing the used brass.  And, I still used a F/L sizer......NOT a S/B die.  So, get your "cam over."  It's your friend, when dealing with military brass.

Aloha, Mark

I spoke with one of the CS people at RCBS. My problem is I'm using a Lee press with an RCBS die. The Lee doesn't "cam over" and therefore will never put the pressure that's needed on the case. He said that if I resized all mybrass in the Lee die, it will probably be fine. I'll still wait until the new case gauge comes in

I use RCBS dies in a Lee Classic single stage press and don't have this problem , seems to resize them fine. Now I'm only using brass from my gun and its not a small base die.

Those are probably the factors that make your and my situation different.

Redding makes a shell holder set for .308 that has shellholders of different heights.....one will probably let you ram those LC cases high enough using the Lee press to make the case small enough near the base.  If you are going to continue with that press that can't cam-over you might try this Redding product.

https://www.midwayusa.com/product/101253343/redding-competition-shellholder-set-1-308-winchester-30-06-springfield-45-acp


I have also experienced the same thing loading for a Remington R25, which has a very tight (for accuracy I presume) chamber........even Federal Blue box factory would not feed.  On that stuff I could chamber the first round, and fire, and the next round would not go into battery.  In that case, magic marker on the ammo showed that it was the base that was too big around.  This was factory Federal no less.  Remington and Winchester factory had no problem loading.

That's why I ended up going to RCBS Small base dies for that rifle, because I had the same problem with the reg RCBS dies.  Their S.B. sizer also bumps the shoulder 1/1000 more than the regular die.  Indeed, I had to "cam-over" even the small base sizer to get them to feed, but you can do that with these Redding shell holders.......sorry, but they are Redding Expensive.  At least you only have to buy them once.

The Remington R25 was worth this hell though.....it's a damn fine shooter.

I'm a fan of small-base dies after this experience......I call them Insurance!  Tell me......what good is all the ammo you reload for a particular AR (using conventional dies where bases are definitely NOT as small as "factory" (even loaded with S.B. sizers bases are bigger than factory))....I say what good is it.....if you ever sell or lose the AR you have now.  There is no insurance the next one you buy will work with your reloads.   I say this knowing full well that the powers that be here on Arfcom already think I'm full of it for having this opinion.

I try to avoid once fired 7.62x51   The vast majority is going to be fired in over-used worn out training MGs that would have over stretched the brass to begin with.   There are a lot of opportunities for de-milled 7.62 brass, that will likely only need to be de-primed and neck sized.

Yeah I hear ya. If I can get these sized right and then fired from my gun, I'll have some good brass. But its a PITA to get there.

No such thing as a training MG. You train with your MTOE’ed equipment. While chambers are gracious and spacious in MG’s, they aren’t that far off from the spec of a 7.62 rifle. After initial prep (mainly recapping and swagging the primer pocket) they’re good to go for 5-7 reloading without annealing...and that’s with warm loads. It’s a bargain if you’re willing to do the extra work. Been shooting 7.62N brass exclusively out of my .308 precision rifles with great results for well over a decade.

So my new Sheridan Engineering slotted case gauge arrived today and I am more confused than ever. I got the slotted gauge so that I could see every point of contact.

First, as the first post says, my newly loaded LC brass will not chamber in my .308 AR-10. I have never had a problem with anything chambering in this rifle. I received the new case gauge and tested them. THEY ARE PERFECT! Not only perfect but they fit in the bottom "c" ring which is SAAMI Spec. And everything inside the gauge fits perfectly. But it won't chamber. Then I tried some stuff I shoot all the time and which chambers with no problem and according to the gauge they are "no go".

Does this make any sense at all?

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I have never had a problem with anything chambering in this rifle.
Which rifle?

I received the new case gauge and tested them. THEY ARE PERFECT!
What did you test?  What is ‘PERFECT’?

Not only perfect but they fit in the bottom "c" ring which is SAAMI Spec.
Again, what fits?

And everything inside the gauge fits perfectly.  But it won't chamber.
What is everything?  What won’t chamber?

Then I tried some stuff I shoot all the time and which chambers with no problem and according to the gauge they are "no go".
Stuff = ???  How do these relate to the ‘stuff’ above?

Does this make any sense at all?
No, not really - too many pronouns!!!  Get rid of all the pronouns and replace them with the noun.

Only if the standard holder is longer than some of those. They're meant to size less than a "SAAMI minimum" holder for longer headspace, and labeled +0.00x".

Unless your Sheridan drop-in gage was cut with the same reamer as your chamber all you are checking with your sized cases is whether or not the shoulder bump and case neck length are within spec.

Use calipers to compare the dimensions of brass fired from your chamber against those using the LC brass or any other cases you have that were fired in another firearm.

If you have a tight chamber and don't want to use calipers then use something like a JP gage -- cut with SAAMI-minimum reamers.

This is a photo (from left to right) showing a Wilson, Dillon, and JP gage and cases entered base-down to give you a general idea of how each is different as they narrow toward the shoulder sizing dimension:

Thanks anyway. I'm dumping this brass. Its way more trouble than its worth. I've wasted a lot of time and money on this crap. I'll use the brass I have and get some cheap factory ammo for the brass.

Maybe try to size them twice, you shouldn't have to after that.
Size a few, take measurements, then if shoulder not bumped enough adjust die down and size them again, or toss them.

I've sized them multiple times. With to different sizers. I'm just chucking it

Sorry you haven’t been able to figure it out.

FOUR more things.....just to be safe.

1:  You DID check to see that there is no bullet or other obstruction in the barrel just past the chamber where a bullet would be stopped?  It's happened before and the result is scary.

2:  Did you ever paint a finished round with black magic marker and try to chamber it to see where the marker gets scraped off?

3:  Picture doesn't look like it, but make sure the bullets aren't seated too long and into the lands when you chamber them.   Also can make lots of scary pressure.

4:  Your rifle is really a .308 and not a .260, or 7mm-08.  I thought I had a .243 custom Mauser in my hands until I tried to load one....turned out to be necked down to .22!

If they have been sized multiple times and they still do not to fit, then the brass is harder than anything I've ever loaded, and I've loaded lots of LC .762 for my Remington AR10.  Bad dies, and bad gauges.....not very likely.........

Before you toss it all send a few pieces to someone here like the mod if you want.....to get another set of eyes on it.  There's got to be a reason.  And you know..... the education you might get is worth more than that brass.

1: You DID check to see that there is no bullet or other obstruction in the barrel just past the chamber where a bullet would be stopped? It's happened before and the result is scary.

Yes, the chamber and barrel are clear

2: Did you ever paint a finished round with black magic marker and try to chamber it to see where the marker gets scraped off?

Yes, most of it seems to be along the base. This doesn't make sense though. The cases that won't chamber slide easily in and out of the gauge

3: Picture doesn't look like it, but make sure the bullets aren't seated too long and into the lands when you chamber them. Also can make lots of scary pressure.

The bullets are seated at their proper COL and they do not extend past the end of the gauge

4: Your rifle is really a .308 and not a .260, or 7mm-08. I thought I had a .243 custom Mauser in my hands until I tried to load one....turned out to be necked down to .22!

Yes, it is a .308

If they have been sized multiple times and they still do not to fit, then the brass is harder than anything I've ever loaded, and I've loaded lots of LC .762 for my Remington AR10. Bad dies, and bad gauges.....not very likely.........

I wonder if the fact that my barrel is match grade has anything to do with it. I guess I'm thinking of it being a tighter chamber?

Yes it could, my Remington sure was.......and mg brass is blown out at the base sometimes, so a smaller chamber is a bigger problem.  You've got to find a way to push that brass in further.  Maybe use a spare shell holder and grind the top down a little at a time...(that would be cheaper than the Redding set anyway).  Of course coming with that is more shoulder bumping, a necessary evil that might have to happen once, because once the brass is "fixed" future resizing will be more normal.

I don't understand why the gauges.........don't.  But I've see that too.  The best gauge is your chamber......or one made from the same reamer as your chamber.  "bad gauges.....not very likely"......then again, they are made for what chamber?  Not yours obviously.

How much brass are you dealing with here?

About 700.

Most?  The first question is was there ANY paint scraped off of the shoulder....as if the shoulder was pushing hard against chamber's shoulder?  Can you (did you) measure the distance on a round that does chamber, from the base to the middle (datum point) of the shoulder.....then measure the same on the LC round that won't chamber?

That's the first thing you gotta rule out.

Then measure the diameter of the part of your painted case where the scratched off paint is and comparatively measure the same point on your commercial brass that can and has chambered easily.  Talking about measuring diameters here.