Just need a little input. Not my reloading problem but a long range friends. He called for the 3rd time on a problem he was having loading 308s. He loaded a mess and almost 2 of 3 would not chamber in an M-1A. Suspected it may have been the cases as they came from Aberdeen Proving Ground. Either from GE guns or M-60s. Also he got a Small Base die set from RCBS. Re-did the whole batch and loaded some in commercial cases to take up the loss of APG cases. About 1 of 3 still didn't chamber. 2 different sizing dies and still no joy. I got him to check length of the the cases and even at minimum length they still are very tight even in a bolt gun. I am thinking the cases are too long to the shoulder or too wide at the shoulder(like the case may have been slightly squashed). Anyone else have any ideas
Help needed on 308s
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Enigma
US Veteran
Do you have a sizing gauge?
Something I found out that I was doing on 30-06 cases was that somewhere between bullet seating and crimping I believe that I was flattening the shoulder angle slightly. That's HARD to pick up with a micrometer.
Something I found out that I was doing on 30-06 cases was that somewhere between bullet seating and crimping I believe that I was flattening the shoulder angle slightly. That's HARD to pick up with a micrometer.
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Get a case gauge for checking the resized brass. Some brass fired in grossly oversized chambers, like a machine gun, will not be sized sufficiently just above the extractor groove because there is a very small area there that is untouched by the die. Trimming will usually be necessary with at least some of your brass, maybe most of it.
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Ivan the Butcher
Member
By judging how far in the case goes, will give you an idea of what is or at least isn't the problem.
Also, Do all factory ammo feed all the way without fail or problem?
Are all his cases trimmed to same length, if not the case mouth will be crimped into the canalure and cause shoulder to bulge.
Last question: Has he checked his chamber for obstruction, powder residue build-up, or a portion of case neck?
Ivan
Redding makes a die you can run loaded ammo in called a "Body Die" (Doesn't touch the neck or crimp) but will remove any slight bulges from the shoulder.
Also, Do all factory ammo feed all the way without fail or problem?
Are all his cases trimmed to same length, if not the case mouth will be crimped into the canalure and cause shoulder to bulge.
Last question: Has he checked his chamber for obstruction, powder residue build-up, or a portion of case neck?
Ivan
Redding makes a die you can run loaded ammo in called a "Body Die" (Doesn't touch the neck or crimp) but will remove any slight bulges from the shoulder.
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Make sure the brass is trimmed to minimum length after sizing....
I shot with a fellow competitor in my High Power rifle days that was trimming the casings before he sized them....no wonder has having problems..
Been using a Dillon case gauge and an RCBS .308 Case micrometer for many years to ensure that all is right. My dies are also Dillon and once properly set up I have no need for a small base die even using M60 fired brass...
Randy
I shot with a fellow competitor in my High Power rifle days that was trimming the casings before he sized them....no wonder has having problems..
Been using a Dillon case gauge and an RCBS .308 Case micrometer for many years to ensure that all is right. My dies are also Dillon and once properly set up I have no need for a small base die even using M60 fired brass...
Randy
I have used some of those cases and I have to resize them twice. Sorry...I just do it twice for my peace of mind.. When reloaded they fit te only 308 I have, A very accurate(and ugly)788 Remington. I do trim to the same length etc etc. But I only loaded 40 or so. I may shoot them in the next year. I think the guy may be mashing the case a bit myself...reducing the shoulder angle and takinf a bit of the taper from the case. I taught this fellow how to reload and will tell you he is very meticulous. One of the only people I shoot reloads he has made in fact. He has tried the rounds in a Rem 700 and a Savage as well as the M1A. Oh and a SMLE chambered in 308. Darn chamber on the SMLE accepts anything. LOL I made a body die by taking the neck out of a Lyman 308 die with the lathe. Factory ammo feeds and functions just fine...all cases are trimmed to same length etc etc . I am going to tell him to try another new shell holder. I may even send him my Redding shellholder lit..If his shellholder is out of spec(as in shorter) wouldn't that make the die size the case down farther..possibly collapsing the shoulder area down. I may be off on that thought..
gwpercle
Member
Do not over crimp...it will make an almost imperceptible bulge at the shoulder and the case will not chamber.
Seat a few bullets...no crimp and see if they will chamber.
This gave me fits in a 30-06 . After backing off the crimp every one would chamber .
Gary
Seat a few bullets...no crimp and see if they will chamber.
This gave me fits in a 30-06 . After backing off the crimp every one would chamber .
Gary
In most dies the base of the case will be sized down to correct spec's....
99% of the time the problem lies in the shoulder of the case.
I only used Rem/Win 308 ammo in my 308 semi-auto, so I did not have feeding problems.
With GI brass, one must take extra care that the case hits spec's and the shoulder
has not moved forward or in the case of MG use, expanded over spec's.
Milt. brass is ok but I use it for light target loads, to keep expansion and pressures to a minimum.
With a good shell holder and a die set correctly, a 308 case, should not cause problems.
Good luck.
99% of the time the problem lies in the shoulder of the case.
I only used Rem/Win 308 ammo in my 308 semi-auto, so I did not have feeding problems.
With GI brass, one must take extra care that the case hits spec's and the shoulder
has not moved forward or in the case of MG use, expanded over spec's.
Milt. brass is ok but I use it for light target loads, to keep expansion and pressures to a minimum.
With a good shell holder and a die set correctly, a 308 case, should not cause problems.
Good luck.
I buy bulk once fired 5.56 and 7.62 Lake City cases and size then first with a small base die and return them to minimum SAAMI dimensions.
A case fired in a semi-auto needs to be .003 to .005 smaller in diameter than its fired diameter. This allows the case to spring back from the chamber walls and extract reliably.
With once fire brass you are dealing with brass spring back after sizing. Meaning the case wants to spring back to its fired size.
So when dealing with once fired military brass a small base die will compensate for the brass spring back. Then thereafter a standard sizing die should work when the cases are fired in your chamber.
Below Forster .308 sizing die types.
A case fired in a semi-auto needs to be .003 to .005 smaller in diameter than its fired diameter. This allows the case to spring back from the chamber walls and extract reliably.
With once fire brass you are dealing with brass spring back after sizing. Meaning the case wants to spring back to its fired size.
So when dealing with once fired military brass a small base die will compensate for the brass spring back. Then thereafter a standard sizing die should work when the cases are fired in your chamber.
Below Forster .308 sizing die types.
schutzen-jager
Member
common problem if cartridge OAL length is loaded to 7.62X51 specs - the NATO chambers are longer then .308 commercial ones -
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The use of a small base sizing die may insure that 100% of once-fired brass will chamber, however, I would suspect that brass life will be shortened considerably with the use of such a die.
My experience with once-fired 5.56 brass of unknown origin indicates that only about one case in every 50 or 100 will not pass a case gauge test after using a standard sizing die. Such cases are discarded.
Brass life will be normal if cases are sized just enough to enter a case gauge without difficulty. This, of course, will require the die to be adjusted for full-length sizing or just short of full-length sizing.
I've never seen a need to crimp .223 / 5.56 brass even the slightest amount, but the procedure likely won't hurt anything if done right. A sized case neck should provide adequate tension to hold a bullet in place.
My experience with once-fired 5.56 brass of unknown origin indicates that only about one case in every 50 or 100 will not pass a case gauge test after using a standard sizing die. Such cases are discarded.
Brass life will be normal if cases are sized just enough to enter a case gauge without difficulty. This, of course, will require the die to be adjusted for full-length sizing or just short of full-length sizing.
I've never seen a need to crimp .223 / 5.56 brass even the slightest amount, but the procedure likely won't hurt anything if done right. A sized case neck should provide adequate tension to hold a bullet in place.
RDub
Member
Is a Small Based Die being used?
Measure the base dimension just above the extraction groove, and measure at the top of the shoulder. Then measure this on a factory load and see what the differences are. If there is a significant difference then you need to go a step further.
I've found, especially on once fired machine gun brass, that the only way to sufficiently size the brass back down close to factory specs is to use an RCBS Small Base Die. Standard sizing dies just won't do it at times.
This 'should' get your brass back down close to factory dimensions as long as you turn the die an additional quarter turn past shell holder touching the die at top of stroke. At times I've even had to run the brass into the SB sizer a second time.
Measure the base dimension just above the extraction groove, and measure at the top of the shoulder. Then measure this on a factory load and see what the differences are. If there is a significant difference then you need to go a step further.
I've found, especially on once fired machine gun brass, that the only way to sufficiently size the brass back down close to factory specs is to use an RCBS Small Base Die. Standard sizing dies just won't do it at times.
This 'should' get your brass back down close to factory dimensions as long as you turn the die an additional quarter turn past shell holder touching the die at top of stroke. At times I've even had to run the brass into the SB sizer a second time.
bigggbbruce
Member
Same problem I had with my FN FAL. I had found that I had slightly crushed the shoulder when seating the bullet. When bullet entered the case it was noticeably tight.
I took my deburring tool and beveled the edge on the neck.. pretty much solved problem.
I took my deburring tool and beveled the edge on the neck.. pretty much solved problem.
ArchAngelCD
Moderator, SWCA Member, Absent Comrade
Small base die needed
For my M1A Loaded, I use a case gauge to check every case. After Sized and trimmed the gauge will identify any cases that are not exactly to spec. This is an important step when loading for a semi auto rifle. Also, make sure the primers are seated slightly below the level of the case. A high primer can allow the rifle to fire when the bolt is not fully in battery. In my experience loading for an M1A just takes a little more time and care. Hope this helps.
The problem with most case gauges is they only check case headspace and not case diameter. And do not work well with cases not fired in your chamber.
Below is a once fired Lake City 7.62 case that has not been resized in a Dillon gauge.
Below is the same case in a JP Enterprise case gauge showing that the gauge is smaller in diameter. These gauges are cut to minimum SAAMI dimensions. Meaning the same size as new unfired ammunition.
I buy bulk once fired Lake City 5.56 and 7.62 cases and size them with a small base die. I also pause at the top of the ram stroke 4 or 5 seconds to reduce brass spring back. After sizing each case is checked in a JP Enterprise case gauge. And if it passes the plop test it will fit in any chamber.
[ame="https://www.youtube.com/watch?v=Gjpf6GbQPlw"]https://www.youtube.com/watch?v=Gjpf6GbQPlw[/ame]
Below the newer JP Enterprise gauges are made of stainless steel and no longer made of aluminum.
[ame="https://www.youtube.com/watch?v=hmyqx_F-oHY"]https://www.youtube.com/watch?v=hmyqx_F-oHY[/ame]
Bottom line, you are dealing with brass spring back after sizing because the cases were fired in larger diameter military chambers. And a small base die will reduce the case body diameter more. And pausing at the top of the ram stroke reduces brass spring back.
And once the cases have been fired in "YOUR" chamber a standard sizing die can be used after the case is fire formed to your chamber.
Think about the Lee undersize pistol dies that size the case .002 to .003 smaller in diameter than a standard die. These under size dies are used by competitive shooter who use range pickup brass. And these under size dies compensate for cases fired in larger diameter chambers and older work hardened brass that springs back more after sizing.
Below is a once fired Lake City 7.62 case that has not been resized in a Dillon gauge.
Below is the same case in a JP Enterprise case gauge showing that the gauge is smaller in diameter. These gauges are cut to minimum SAAMI dimensions. Meaning the same size as new unfired ammunition.
I buy bulk once fired Lake City 5.56 and 7.62 cases and size them with a small base die. I also pause at the top of the ram stroke 4 or 5 seconds to reduce brass spring back. After sizing each case is checked in a JP Enterprise case gauge. And if it passes the plop test it will fit in any chamber.
[ame="https://www.youtube.com/watch?v=Gjpf6GbQPlw"]https://www.youtube.com/watch?v=Gjpf6GbQPlw[/ame]
Below the newer JP Enterprise gauges are made of stainless steel and no longer made of aluminum.
[ame="https://www.youtube.com/watch?v=hmyqx_F-oHY"]https://www.youtube.com/watch?v=hmyqx_F-oHY[/ame]
Bottom line, you are dealing with brass spring back after sizing because the cases were fired in larger diameter military chambers. And a small base die will reduce the case body diameter more. And pausing at the top of the ram stroke reduces brass spring back.
And once the cases have been fired in "YOUR" chamber a standard sizing die can be used after the case is fire formed to your chamber.
Think about the Lee undersize pistol dies that size the case .002 to .003 smaller in diameter than a standard die. These under size dies are used by competitive shooter who use range pickup brass. And these under size dies compensate for cases fired in larger diameter chambers and older work hardened brass that springs back more after sizing.
trapper9260
Member
This is what I found in LC brass then regular commercial brass. I had to trim most of the LC brass I bought beside ream out the primer pocket on them.I reload for a Moss. bolt 308 win and a DPMS AR-10 308 and I do not have problems chamber. I use the RCBS small base dies and also do not put hardly and crimp if any I shoot alot of cast in both of my and I use the LFC die also after all is loaded. By the way when load military brass it it thicker then commercial brass, when you load for one you go with the data of the min start and then you need to do the same with the other also. one will be more pressure then the other. Also if you can take the brass before you load it after you size and trim .just put the bullet in it and use the FCD and then you will know more of what is going on. Also some chambers are tight.What will work in one go of the round dose not mean it will in a different make and chamber. I found that out in some I have .Hope this help.
A couple of thoughts here.
1. Is the M1A a rack grade or Super Match? I'd expect the SM to have a tighter dimensioned chamber.
2. Does he have a case gauge? If so, is he using it both on sized dies and loaded ammo? It would appear he doesn't.
3. Has he tried any surplus 7.62 mm loaded ammo for function? Might not necessarily be his loads.
4. I've used surplus 7.62 brass in a bolt gun, only using a properly set up standard dimension (Dillon) die. There are any number of cases I've noted by the extractor mark and effort needed to size that have been through full auto weaponry. Still have not needed a small base die.
5. I've experienced the case shoulder bulge from over crimping myself and it can cause problems. However the biggest issue I have had with any surplus brass was when my sizing die slipped ever so slightly in adjustment and was leaving the shoulder to base dimension too long.
As others have noted, he needs a case gauge or 2 and a very careful check of first principles. Blindly adjusting sizing dies to factory directions may not produce the correct result. I've gone to Dillon sizing dies in a couple of calibers exactly because you can set the exact headspace you need.
I'd also suggest a Lyman M die to expand the neck diameter uniformly, this can be done while priming if he's not using a progressive loader.
Finally the crimp. I cheat and use a loaded arsenal/factory round to set initial taper crimp. Slight adjustments will probably be necessary, but you don't really need all that much crimp. If the bullet doesn't set back after being loaded in the chamber one or two times, you're good.
1. Is the M1A a rack grade or Super Match? I'd expect the SM to have a tighter dimensioned chamber.
2. Does he have a case gauge? If so, is he using it both on sized dies and loaded ammo? It would appear he doesn't.
3. Has he tried any surplus 7.62 mm loaded ammo for function? Might not necessarily be his loads.
4. I've used surplus 7.62 brass in a bolt gun, only using a properly set up standard dimension (Dillon) die. There are any number of cases I've noted by the extractor mark and effort needed to size that have been through full auto weaponry. Still have not needed a small base die.
5. I've experienced the case shoulder bulge from over crimping myself and it can cause problems. However the biggest issue I have had with any surplus brass was when my sizing die slipped ever so slightly in adjustment and was leaving the shoulder to base dimension too long.
As others have noted, he needs a case gauge or 2 and a very careful check of first principles. Blindly adjusting sizing dies to factory directions may not produce the correct result. I've gone to Dillon sizing dies in a couple of calibers exactly because you can set the exact headspace you need.
I'd also suggest a Lyman M die to expand the neck diameter uniformly, this can be done while priming if he's not using a progressive loader.
Finally the crimp. I cheat and use a loaded arsenal/factory round to set initial taper crimp. Slight adjustments will probably be necessary, but you don't really need all that much crimp. If the bullet doesn't set back after being loaded in the chamber one or two times, you're good.
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