308 Loads not chambering in AR, need advice

[9mmSkeeter]

I recently got into reloading 308. I bought a bunch of discounted brass from a secret source (shhhh) - various brands, mostly LC, some Winchester, some PMC, Lapua, etc etc. and I bought four pounds of various known 308 powders.

I also purchased a Lyman 3-die set (quick Neck Sizer as well as Full Length Sizer and of course the bullet seating die). I love Lyman Carbides, about 80% of my die sets are Lyman.

I made the smart decision of building about 50 test loads using three or four different powders I was able to acquire and once the snow finally melted I was going to go shoot my Smithy AR-10 on a beautiful sunny day. Drove an hour and got there, and the !@#%^ wouldn't chamber a single round. I had to pound the bolt open with a cleaning rod and hammer (thank God I brought those), marred the finish on the bolt, and then "mortared" the rounds out by slamming the buttstock on the bench with the charging handle held. It stuck them in there tight too.

Did this about 6 times with various rounds/brass, nothing worked.

So being a good internet user I decided NOT to post about this, found out that the full length size was something I needed to do. I previously just used the neck sizer.

Proceeded to pull all the rounds and re-size, and re-load a handful. None of them chambered. Borrowed a buddy's bolt action, would not chamber there either.


Called S&W. They said to try factory ammo and if that didn't work, send it in.

Finally found a box of PMC FMJs sitting around and purchased them at an inflated price. Wouldn't you know, it chambers. So I took out my trusty calipers. Because you know, it has to be about dimensions, right? Everything lined up. The length all the way up, the width, the neck width, the bullet.

So now I'm stumped. Here's a pic of how my AR marks the brass when I finally am able to eject it :

https://ibb.co/f10651C

I've loaded tons of 30-06 before with no issue. I wonder what the deal is here? Is this still an issue with Smith & Wesson?

Thanks in advance, I'm really not sure what to do at this point.

[zoomie]

I'd start with something like this:

{Edit: Zoomie, please read the board rules on posting copyrighted materials and on hot-linking like that.}

[HiBC]

A very common problem (perhaps) that I have probably answered 20 times here.
When you put your seater die in the press,did you screw it in till it contacted the shellholder?

If you did,thats wrong. The seater die crimps. Its likely you forced maximum crimp on the round. But the crimp had no place to go,
So the shoulder collapses. Outward. It grows larger. As the bolt forces the enlarged shoulder into the tapered chamber,it gets stuck.

Now,back your seater die out about 5 turns from the shellholder. Put a piece of sized brass in the shellholder and run the ram up to the top. Now,with your fingers,screw the die down till you feel the crimp feature in the die contact the case mouth. Stop. Now,with the ram still up, lookee how far off the shellholder your die is. See that gap? Thats how much you crushed your ammo.
Back the die off anothe 1/4 turn or so. Now find a washer or feeler gauges or something you can use to repeat that gap and keep it in your die box.

You maybe could have learned this the easy way reading die instructions or a loading manual,

But I swear about every third person that decides to load for an AR writes in

"My ammo gets stuck!!"

OK,! Have fun!

[MarkCO]

Good stuff HiBC.

The full length sizing die 9mmSkeeter, is different. I like to use Competition Shellholders from Redding to work the shoulder as little as possible. If that is confusing, you can set the dies the way the manufacturer tells you do, just realize that, in most cases, you will have brass that is getting worked more than I like and the headspace is more than is beneficial for best accuracy.

[Renquestor]

With AR platform rifles you sometimes need Small Base dies that resize the brass to just below SAAMI minimum specs.


Sent from my iPhone using Tapatalk

[gwpercle]

Small Base Resizing Die ... required by some , but not all , semi-automatic rifles .

Not a S&W thing but a chamber specification thing . Tolerances on chamber size and resizing die size can stack against you ... a slightly large resizing die and a slightly tight chamber add up to ...well you know ...not chamber .
The small base die sizes the brass down slightly below specification allowing it to chamber in a tight chamber .
No way all that range brass was going to work with just a neck size ... You "might" be able to adjust the die or use a thinner shell holder to size the brass down a little more ...perhaps then it will chamber ... if not ... a Small Base Sizing Die will be your only option .

Gary

[9mmSkeeter]

Thanks for the information everyone.

The dickishness from Hibc was not needed though. Maybe he needs his morning coffee?

[HiBC]

Just to hopefully clarify

There is problem 1) that I described . Setting the seater die. A common operator error.

Potential problem 2) the resized length of your cartridge brass,case head to shoulder. Especially using scrounged brass not fired in that gun,brass that is too long wont let the bolt close into battery. Necksizing is not going to work for you.
The term "headspace" describes the length of the rifles chamber,from breech face to (in this case) the shoulder.
The term "Head clearance" describes the clearance ,lengthwise,between the breech face and the cartridge head with the cartridge seated against the chamber shoulder.

This length adjustment to the brass is one part of resizing. Again,the rifle needs some head clearance for the semi-auto to freely close into battery.

For bolt guns,a lot of folks like .002 in. Until you are sure yu can control everything precisely,.004 might be better for an AR. .006 is suggested for Garands and M-14 s.

There are ways to measure it. A good tool has been suggested above, Its frequently called a "Bushing type cartridge headspace gauge" Thats not quite technically correct. Cartridges do not have headspace,but it will get you the right tool. Wilson makes a good one. The tool has a high/;low limit step .

IF you size your brass to fit that high/low limit,your ammo is SAAMI spec for case length and should ft any SAAMI gun. A bit more advanced technique is tuning that length to your rifle.This will extend case life by minimizing stretch.. Note,that gauge is for checking length,not diameter.

Item 3) Small base dies. These are designed to size diameter to minimal diameter . They are available and often mentioned. Apparently some rifles need them. In over 50 years of loading for many semi autos, I have never needed a small base die.

I wonder if they might be needed for Remington Woodmasters or Win model 100 rifles. I have never loaded for those.

For an AR. I won't say "never" to a small base die set. But I would be slow to buy one.

1) Seater die/crimp 2) Resizing head clearance length 3) Resized diameter.

[44 AMP]

I'll try to keep it simple. Factory ammo fits and works ok, so clearly your problem is what ever you are doing or not doing isn't getting you that fit.

Some "mil spec" guns have "oversize" chambers. Belt fed machineguns nearly always do. And some will let fired brass stretch too much to fit in a tight civilian chamber. In some cases even small base dies are not enough and brass spring back leaves the cases still to large. Uncommon, but it can happen.

I strongly advise you to have your rifle at the loading bench so you can check the fit of your sized brass right then.

Next, I advise you remove the firing pin (for safety) and use the rifle to check the fit of your loaded ammo. Do this at home before driving hours to the range, you won't be sorry.

If resized fired brass won't chamber, that is where something needs to change. If it does but loaded ammo won't, then the change needs to be done in the seating/crimping stage. Some of the pitfalls there have already been mentioned, a crimp done wrong can keep ammo from chambering.

Here's another tip that may or may not be useful, if you get your AR bolt stuck ALMOST all the way closed, see if you can separate the upper and lower. If you can, you can then use a proper punch to apply force on the front edge of the rear ring of the bolt carrier, driving it back, and hopefully freeing the stuck parts, without doing a rod down the muzzle, or beating on the outside of the BCG or "mortaring' the rifle, which is something that always horrifies me as advice. Its a combat expedient to be used when your butt is on the line, otherwise you should do something other than banging the stock on the ground and hoping...

With brass checked for length (trimmed if needed), run the press ram all the way UP, then screw the FL die all the way down to a firm contact with the shellholder. THEN size some brass, and check it for fit in your rifle chamber.

Forget (for now) all the stuff about neck sizing and "bumping" the shoulder back 0.xxx". That stuff is for AFTER we get reliable feeding, chambering, and function.

IF the test batch of FL sized brass doesn't fit you chamber, size them again, and let each case "linger" a bit fully in the die, so that the oversize brass "gets used to being smaller" and springs back less when out of the die. Check chambering again and see if that changes things any in your rifle.

IF not, you can consider small base dies, or a different sizer die, or tossing the brass out (into scrap recycle) and just getting more, and perhaps NEW brass.

I will admit to not having loaded .308 Win for an AR rifle. Have done .223 in ARs and the principles are the same. Have loaded .308 and used in M1A and FAL without the need for small base sizer dies.

Case gauges are nice, but not an absolute necessity, the gauge that really matter is your rifle chamber. USE it correctly for testing as you construct you ammo and you will have ammo that fits it. Then go to the range for live fire testing.

Good luck let us know how it goes, we'll help and share our experience any way we can.

[Metal god]

Some "mil spec" guns have "oversize" chambers. Belt fed machineguns nearly always do. And some will let fired brass stretch too much to fit in a tight civilian chamber. In some cases even small base dies are not enough and brass spring back leaves the cases still to large. Uncommon, but it can happen.

I strongly advise you to have your rifle at the loading bench so you can check the fit of your sized brass right then.

Next, I advise you remove the firing pin (for safety) and use the rifle to check the fit of your loaded ammo. Do this at home before driving hours to the range, you won't be sorry.

With brass checked for length (trimmed if needed), run the press ram all the way UP, then screw the FL die all the way down to a firm contact with the shellholder. THEN size some brass, and check it for fit in your rifle chamber.

Forget (for now) all the stuff about neck sizing and "bumping" the shoulder back 0.xxx". That stuff is for AFTER we get reliable feeding, chambering, and function.

IF the test batch of FL sized brass doesn't fit you chamber, size them again, and let each case "linger" a bit fully in the die, so that the oversize brass "gets used to being smaller" and springs back less when out of the die. Check chambering again and see if that changes things any in your rifle.

+1 on that , first size your case down as small as you can and trim to length , then see if the EMPTY case chambers . If it does proceed to

A very common problem (perhaps) that I have probably answered 20 times here.
When you put your seater die in the press,did you screw it in till it contacted the shellholder?

If you did,thats wrong. The seater die crimps. Its likely you forced maximum crimp on the round. But the crimp had no place to go,
So the shoulder collapses. Outward. It grows larger. As the bolt forces the enlarged shoulder into the tapered chamber,it gets stuck.

Now,back your seater die out about 5 turns from the shellholder. Put a piece of sized brass in the shellholder and run the ram up to the top. Now,with your fingers,screw the die down till you feel the crimp feature in the die contact the case mouth. Stop. Now,with the ram still up, lookee how far off the shellholder your die is. See that gap? Thats how much you crushed your ammo.
Back the die off anothe 1/4 turn or so.

Id say 1/2 to full turn otherwise very much could be the problem .

Those two things together will almost certainly result in a round that will chamber . If not you may need to go to a small base die .

All that said , do you have a comparator to check and factory brass that was fired in the rifle ? Or to compare factory new cartridge head to datum measurement to your FL sized cases ?

[44 AMP]

All that said , do you have a comparator to check and factory brass that was fired in the rifle ? Or to compare factory new cartridge head to datum measurement to your FL sized cases ?

At the risk of starting an off topic argu..er..discussion, at this point, I don't think the OP needs a comparator and it would only confuse the issue.

I think the point right now is to make full length sized ammo that fits and functions, and doing less than FL sizing is something for after he gets his reloads working.

With the sizer cranked all the way down, there's only one result and we expect that to be a min spec size that should fit in every chamber. That's the point of FL sizing. Getting data from fired cases (no matter what system is used to measure) is, essentially irrelevant, until AFTER we get consistent fit and function from FL sized brass.

Adjusting (backing off) the sizer die to get s specific measurement that is not full FL sizing the case body is for later down the road. walk, then jog, THEN run...

[stagpanther]

Get a RCBS small base full length die. Your problem is your brass has conformed to a different chamber. I would go as far as to say never use a neck size die for an AR. I'm beginning to doubt them for even bolt guns.

{Image removed for lack of indication permission of the copyright owner was acquired. See board rules about posting copyrighted materials.}

[IMtheNRA]

I don't think you need a small base die yet. I bet that you're just not resizing your cases enough.

A stuck round is the classic symptom of a sizing die that needs to be screwed down a little more.

[Shadow9mm]

So, I ran into this issue recently with 308 and my bolt gun. I did not have my die adjusted down far enough. I had it firmly touching the shell plate but that was not enough because when I sized the brass there was a gap between the die and the shell holder.

What I would recommend is getting the LE Wilson Headspace Gauge. They are on sale for $26.54 on midway right now.
https://www.midwayusa.com/product/1016251573

The gauge has a minimum and maximum headspace line. You can use this when adjusting your die to make sure your are sizing enough.

If you want to get into detail. You can fire factory ammo in your gun and put the fired casing in the gauge to measure the head space for the fired casing. It will also give you a neck length gauge to tell you if you need to trim your necks.

As mentioned it is generally a very bad idea to neck size for semi auto guns. Some competition shooter say never to neck size (Eric Cortina) but I'm trying to stay on topic.

Also as mentioned, it is generally recommended to use small base dies for semi auto guns. With that said I used a regular Lee 223 die for a long time for my AR with no issues.

I would start with the case gauge to make sure you are getting the cases properly sized.

[IMtheNRA]

RCBS Precision Mic is even better.

[Shadow9mm]

Originally Posted by IMtheNRA

RCBS Precision Mic is even better.

Never heard of it. Interesting tool but it looks to be touch on the advanced side and might be overkill for what the OP is needing. the Precision Mic can measure min and max headspace however it appears to be set up more as a comparator to measure the guns headspace and compare it to the brass you are resizing to just bump the shoulder.

This being a semi auto gas gun, just bumping the shoulder is probably inadvisable. Having a gauge that quickly and easily visually shows min and max headspace and can be measured with a caliper is what I would go with.

[Metal god]

At the risk of starting an off topic argu..er..discussion, at this point, I don't think the OP needs a comparator and it would only confuse the issue.

I think the point right now is to make full length sized ammo that fits and functions, and doing less than FL sizing is something for after he gets his reloads working.

Maybe confusing but I/we don't know his level of experience or the reason I asked the question . If he has the comparator he can compare sized cases to factory cases if the same or close enough to , the issue is more likely the seating die crimping to much . I could have been more clear but I was just trying to have him work on one thing at a time and if case head space is good from the start he can go straight to adjusting the seating die . On the whole I think your right though . maybe he should start with firm contact between the FL die and standard shell holder and see what he gets , then adjust the seating die if need be .

Stag , That shirt is funny as all get out

[Shadow9mm]

Could be the crimping. Could be the sizing, could be both.

Come to think of it, easiest thing to do would be resize a couple pieced and see if the unloaded brass will chamber. If it chambers its the crimp. If it does not chamber, it is not getting sized enough. Kind of like a plunk test on a handgun.

Granted it will not tell the OP if that ammo is in spec, but chambering in the gun and figuring out the source of the problem is a step in the right direction and it should work in the gun.

Also, I had terrible luck with the seat/crimp combo dies. I use the Lee Factory Crimp die for all crimping, easier to set up, no way to mess up the shoulder.


Metal god. The shirt is from Eric Cortinas website. He is big on "do no neck size". I love the shirt but cant bring myself to put a literal target on my chest, just in case.

[hounddawg]

Come to think of it, easiest thing to do would be resize a couple pieced and see if the unloaded brass will chamber. If it chambers its the crimp. If it does not chamber, it is not getting sized enough. Kind of like a plunk test on a handgun

::thumbsup::

[stagpanther]

Stag , That shirt is funny as all get out

I know--saw it on an Eric Cortina video and just had to get one.

[HiBC]

The dickishness from Hibc was not needed though.

The thing about handloading is you do not always get a second chance to get it right.
Reading the instructions and studying the reloading manual saves a lot of time and trouble.

Not doing that is one way to earn the "little Richard" award.

I took a fair amount of time and trouble to give you a good answer.

[Shadow9mm]

Originally Posted by HiBC

The thing about handloading is you do not always get a second chance to get it right.
Reading the instructions and studying the reloading manual saves a lot of time and trouble.

Not doing that is one way to earn the "little Richard" award.

I took a fair amount of time and trouble to give you a good answer.

Still does not address the fact that you could have said it nicely rather than in a churlish manner.

[44 AMP]

Come to think of it, easiest thing to do would be resize a couple pieced and see if the unloaded brass will chamber. If it chambers its the crimp. If it does not chamber, it is not getting sized enough. Kind of like a plunk test on a handgun.

Which is what I said in post #9.

I've always gotten good results sizing on a single stage press, and O frames are the best. I've found progressives and turret presses, while fine for seating just have too much give built in (so the parts can move) for best results FL sizing rifle brass.

Been using the same Lyman FL sizer die in .308Win, that I got in 1973, I use it in an RCBS JR press these days, screwed down firm on the shellholder with all the slack out of the ram.

I seem to be in a minority these days with everyone saying how you need to size your brass to just barely fit in the chamber, and while a good approach with a precision bolt gun, I think its the wrong thing for semi autos. I WANT min sized ammo for the most clearance I can get when feeding a semi auto. With many semi autos all you have is the force of the recoil spring and the clearance of the ammo when feeding. Only a few these days have operating handles that work both ways.

My FL Lyman .308 sizer die (screwed all the way down like the instructions say) has produced acceptable ammo for several different bolt and lever guns and also for an M1A, an FAL and an H&K 91. Never had any issues with cases not chambering ok, and also never had issues with brass life.

Yes, cases that fit the chamber "tightest" seem to give the best accuracy I gladly give up a tiny fraction of accuracy (which is most likely beyond the capability of my rifles and shooting skill anyway) for reliability.

I'd take a 3 or 4MOA rifle that works EVERY TIME over a 1MOA gun you have to hammer shut or bang on the ground to get open.

[Bart B.]

Originally Posted by 44 AMP

Adjusting (backing off) the sizer die to get s specific measurement that is not full FL sizing..........

I asked several sizing die makers what full length sizing means. All said that case outside dimensions except length and rim-to-extractorgroove must be made smaller. Die doesn't have to touch the shell holder. Otherwise it's partial full length sizing.

Most folks agree.

[Metal god]

So the shirt is Eric’s Merchandise ? I’ll need to go to his website to buy it ?