[BigBill]

Food for thought, reloading for the military semi auto's, any caliber/brand.

Now with reloading using the right gun powder with the correct burn rate for the semi auto 308 is very important too with the cycle timing. I use only IMR4895 in all my military semi auto's. And i use the CCI #34 nato primers in all my semi auto's because of the thicker wall the primers have for the floating firing pins. So no slam-fires will occur.

I post this for safety reasons, besafe, beaware if your not sure then ask. I know we have a lot of non posters / just readers on all the gun forums and its good to share info.
Bill

 

[Larry Gibson]

Hi Larry your clearly entitled to your own opinion based on data you have collected over the years. This has been a gray area for me as well as others since I joined the forum. It comes up over and over again. I have not done anything like you in your efforts to support what you said. It was actually this thread that inspired me to ask my own headspace question. Here is the link
http://m14forum.com/gunsmithing/104319-my-turn-ask-head-space-question-please.html
Although I am glad you have never had any problems and your data is well founded, I am going to stick with what a man with way more experience than most fiddling around with these rifles has to say. In my mind I feel they are correct, it just makes sense. Not to mention all the malfunctions that the man has seen caused by the same thing we agree to disagree on. Not looking to discredit you or call you out so to speak. Please don't take what I said as someone looking for an argument please. Had enough of that over the years.

Gus has indeed a lot of experience. But I think you've found from other posts that many of us have a lot of experience also. In addition, let me run a few actual measured psi figures by you. These are not based on "experience" or interpolation of what might be based on headspace varience but on actual measurement of psi's in the same test barrel with a chamber of minimal SAAMI dimensions for the .308W (thats smaller than a NM chamber at minimum headspace BTW).

Psi's listed are average peak pressures based on 10 shot test strings done with SAAMI test specification procedures using the same test rifle with the M43 Oehler PBL.

Winchester 150 gr PP; 55,500 spi
Remington 150 gr CL; 55,700 psi
Federal 150 gr PowerShok; 54,500 psi
Winchester 180 gr SuperX; 52,900 psi
LC 88 M852; 53,900 psi
Federal Gold Match; 54,100 psi
LC 88 M118SB; 59,200 psi
LC 98 M118LR; 60,100 psi

M80 Ball; US and foreign NATO "equivelent":
IVI 70; 58,000 psi
LC74; 52,100 psi
WRA 69; 60,400 psi
LC 74 (different lot than above); 58,200 psi
LC 87; 64,800 psi
LC 90; 59,700 psi
CAVIM; 53,100 psi
61 92 (Chinese); 45,700 psi
OFV 82; 42,600 psi
MAL 11-83; 52,200 psi
Wolf M80; 45,800 psi
FNM 80-49; 50,900 psi


That's just a random sampling commercial (loads usable in the M1As bullet weight range) and milsurp both use and foreign. Note most of the foreign stuff was made for use in FN/FALs and the velocities were lower comsurate with the lower psi's. Note that most all US NATO spec ammuntion is above the commercial .308W in psi. This is not "experience" or interpolation of what psi's might be based on headspace. Again, this is actual psi measurement data.I appreciate your opinion and your staying on the fence. I've no problem with that. I'm just pointing out factual information is all.

Larry Gibson

 

[Lazerus2000]

Excellent post re 7.62 VS .308 WIN ... BUT???

I've a lot of respect for Gus but I've a problem with this statement; "1. Do NOT use standard Nato Spec surplus ammo in a rifle chambered with a NM chamber and set up at the minimum headspace. Even if the rifle functions with no apparent problems, the chamber pressure of each round fired is significantly more than in a proper Nato Spec chamber." The reason is he makes an assumption based on measuring headspace. I wouldn't want to guess at the number of match shooters over the years shooting M1A/M14s with NM who have shot the barrels out using "Nato spec" ammuntion, i.e. M80 XM118, M118, M118 and now M118LR. All without any said pressure problems alluded to.

Additionally I have measured the pressure of those ammuntions in a minimum spec chamber with minimum headspace and another test barrel with a NM chamber with minimum headspace. The measured pressures showed nothing out of the ordinary for such loads and were perfectly within NATO specs and below SAAMI MAP for the .308W. I've also pressure tested numerous foreign lots of 7.62 ammuntion of Nato spec and not of Nato spec. Additionally I've pressure tested numerous brands of .308W commercial ammuntion. The psi MAPs of .308W commercial ammuntion overlaps with those of US made 7.62 Nato with some of each having higher MAPs than the other. Thus it is foolish to say one or the other is loaded to "higher pressure". I wonder if Gus realises that 7.62 Nato Spec ammuntion is developed with safe pressures in test barrels with minimum chambers, smaller than NM chambers? Thus firing those cartridges in slightly larger NM chambers should give less pressure.

.308W or 7.62 NATO.....Much ado about nothing........

And yes I have fired lots of commercial .308W ammuntion through M1A/M14s over 41+ years, some with NM chambers with minimum headspace and others were rack grade rifles with milspec chambers. Not a single problem.

Larry Gibson

EXCELLENT POST regarding chamber dimensions and chamber pressure!!!

I like to set up my range/target use only M14 rifles at .308 GO PLUS .002". So far, I've never found any CLEAN 7.62 NATO ammo that would not chamber easily with a stripped bolt, and fall out easily as well.

For my "field" rifles, which may not get cleaned regularly, I like a bit more margin for error. With the M14 design, I'd personally be more worried about out of battery slam fires partially caused by a too short / dirty chamber, than I would about over pressure loads that are properly seated with the bolt all the way down.
Just my personal opinion,
YPMMV here.

However,
while you clarified chamber pressure concerns,
you left out the issues of slower powders and higher pressure at the gas port, which can beat up an M14.
OR,
with commercially loaded SAMMI spec .308 WIN,
are there no significant gas pressure issues at the M14 gas port?
AND,
you also didn't discuss THE BAD THINGS THAT CAN HAPPEN with an M14 when heavy bullets are loaded to high velocities.

PS: I've shot thousands of rounds of .308 WIN ammo through hundreds of M14 type rifles, mostly through the Canadian Import Chinese clones. Many of these Chinese clones have "VERY GENEROUS" head space. Even so, the number of reported incidents of case separation with FACTORY LOADED .308 WIN AMMO are almost nil up here in the great white North.

However,
we Canucks have a growing body of reported incidents that suggest that with .308 reloads that are stretched in a too long M14 chamber, and then were full length resized, shooting reloaded .308 WIN AMMO in a Chinese long chamber is not a great idea.

Personally, when I want to shoot 200 gr bullets out of a semi auto rifle, I turn to my AR 10. The TEN, which of course has no op rod and uses direct gas impingement, is a lot more forgiving of port pressure variations, and it will shoot reliably group into less than 1" at 100 yds. with factory loaded .308 WIN ammo from 110 grs to 200 grs.
LAZ 1
[.

 

[Larry Gibson]

Lazerus2000;

EXCELLENT POST regarding chamber dimensions and chamber pressure!!!

Thank you for the generous remarks. Let me make comment on specific concerns you present which are legitimate concers.

"However, while you clarified chamber pressure concerns,
you left out the issues of slower powders and higher pressure at the gas port, which can beat up an M14.
OR,
with commercially loaded SAMMI spec .308 WIN,
are there no significant gas pressure issues at the M14 gas port?
AND,
you also didn't discuss THE BAD THINGS THAT CAN HAPPEN with an M14 when heavy bullets are loaded to high velocities."

I was referencing Gus's remarks Do NOT use standard Nato Spec surplus ammo in NM chambers with minimum headspace. I also referenced .308W commercial loads that were appropriate for use in the .308W. Only .308W ammuntion such as the Hornady light magnum or newer super velocity ammo would have issues with higher gas port pressures. Standard factory loads do not.

Also understand the M1A/M14's gas system cuts off the flow of gas pressure when the pressure is sufficient to move the gas pist a very small amount. That is why the M14 never needed an adjustable gas system as it was self regulating for reliable functioning. However, residual pressure still in the case causing it to still grip the chamber can easily cause a malfunction or damage the oprod or breack the extractor. All standard commercial .308W ammuntion is designed to function at the same time pressure curve because of the different gas operated sporting rifles made for it, that time pressure curve is the same for 7.62 NATO.

I didn't discuss heavy bullet reloads because they were the topic of discussion.

PS: I've shot thousands of rounds of .308 WIN ammo through hundreds of M14 type rifles, mostly through the Canadian Import Chinese clones. Many of these Chinese clones have "VERY GENEROUS" head space. Even so, the number of reported incidents of case separation with FACTORY LOADED .308 WIN AMMO are almost nil up here in the great white North.

However,
we Canucks have a growing body of reported incidents that suggest that with .308 reloads that are stretched in a too long M14 chamber, and then were full length resized, shooting reloaded .308 WIN AMMO in a Chinese long chamber is not a great idea.

It's not a good idea in an American made M1A/M14 either. Incipient case head seperation can easily occure with even LC milsurp cases if the cases are sized too much. That is why I recommend RCBS standard X-dies. I also strongly advise to adjust them so the cases are sized only to the headspace of the chamber the ammo is used in. To FL size cases to "fit" within most .308W headspace cartridge gauges is to invite almost certain very short case life.

Personally, when I want to shoot 200 gr bullets out of a semi auto rifle, I turn to my AR 10. The TEN, which of course has no op rod and uses direct gas impingement, is a lot more forgiving of port pressure variations, and it will shoot reliably group into less than 1" at 100 yds. with factory loaded .308 WIN ammo from 110 grs to 200 grs.

Personally I don't shoot 200 gr Jacketed bullets out of my .308Ws, M1A or bolt guns, as 180s fill the bill for me. The 180s, either as reloaded or as commercial ammunition, work fine.

Again, thanks for the comments. As you see I was trying to stick with the topic, not expand it. Not to say the points you mention aren't worth discussion but i was wanting to stick with the thread topic concerning .308W ammuntion in M1As, not reloads.

Larry Gibson

 

[Lazerus2000]

most excellent information ...
sorry if I dragged the thread into other areas of interest,
but a good discussion in any case,
[
Larry Z

 

[82nd ABN]

One of my questions in the thread I started was what causes premature throat erosion in a barrel? I may have twisted up a few rifles so far but I still consider myself a newbie when it comes to these rifles. I may know the mechanics but when it comes to reloading and port pressures seating depths ect I know nothing. My rifles to include my newest ar-10 are all set up with tight chambers. I shoot 175 grain BH match stuff and al the rifles do well with this cartridge. I plan on setting up a reloading bench this winter. Yes I will am still confused as heck on what equipment to get but thats another thread all together. My concern is how not to cause premature wear on the throat.
From what I understand the barss BH uses is Winchester brass. I do plan on reading a few books before I get started and have a friend that will show me the basics. I started competing this year and reloading looks to be a good solution to one increase the number of rounds I can send downrange and two give me the opportunity to learn a new skill that will help me towards my goal of tuning my loads to obtain better accuracy from my rifles. They all shoot well now moa or better.
I might add that I used a obermeyer .308 match reamer to finish ream all my chambers. After speaking to Boots he explained he designed this reamer specifically for the M118 round. From his description, this reamer sets up with a long throat for the larger rounds.

 

[nf1e]

Seems to me the M118 is 7.62X51 and not .308. This should say something about interchangability. I think the importantance of finished case lenght would have more to do with the throat errosion question than which reloading die is being used.
Semper Fi
Art

 

[82nd ABN]

Thanks Art. I'm not sure the BH is an exact copy of the M118LR. I would like to be able to duplicate the load though.

 

[Larry Gibson]

Art

The .308W is the civilain version of the 7.61x51. Winchester was in on the development of the 7.72x51 and released the civilian version as the .308W. Different minimal chamber headspace or other dimensional specs do not alter that fact. Don't want to believe me look up the history in a reputable book.

82ndABN

My concern is how not to cause premature wear on the throat.

"Premature" being the key word; only way is to shoot slow fire only and not let the barrel get hot at all, to clean carefully not allowing the cleaning rod to wear the throat (or muzzle for that matter) and to use bullets that are a tight fit (not too large and not too small) in the throat, leade and groove depth of the barrel. The use of ball powders may help a little as they are "supposed to" burn cooler.

Larry Gibson

 

[82nd ABN]

Thanks Larry. I am heading up by the mall today with the hopes of finding my first of a few books to start my education on reloading. Hoping to find something at the local gunshop. I'll probably wind up ordering from brownells.

 

[nf1e]

Thanks Larry, I think we were saying the same thing. That's the reason for my using them interchangeably for over 45 years. Warren said in his post that he was using a match .308 finish reamer and that it was designed specifically for M118 which is 7.62X51. Same same.Just set headspace longer for M118.Technical is good. Too technical and I go to sleep.
Semper Fi
Art

 

[82nd ABN]

Well just got back from barnes and noble. They had one book but it's a start. It's called the abc of reloading for novice to expert. I'll get another when I'm done with this one.

Even though I'm using that Obermeyer match reamer I'm still setting up the HS to 1.630-1.631. Everything seems to work fine.

 

[geeck]

82nd don't forget that Zediker Download http://www.zediker.com/downloads/m14.html you probably have it already, it's worth a reviewing. There's a lot of good M14/M1A specific information in there.