Lake City brass too big for 308 chamber

[ttuttle]

I have an interesting problem. I bought 300 ea of Lake City brass in 308. I reloaded it with 150 gn Hornady bullets. The problem is the rounds won't chamber in my Garand. My micrometer tells be the base of the brass just ahead of the rim is about .006 thousands too big as if the brass has stretched. It goes thru my resizing die without a problem but still won't chamber the last 3/8 inch of the round. The neck diameter on some of them, but not all, is .003 too big. I thought LC brass is thicker and therefore has less tendancy to stretch. Any ideas or suggestions would be appreciated.

 

[scap99]

I have an interesting problem. I bought 300 ea of Lake City brass in 308. I reloaded it with 150 gn Hornady bullets. The problem is the rounds won't chamber in my Garand. My micrometer tells be the base of the brass just ahead of the rim is about .006 thousands too big as if the brass has stretched. It goes thru my resizing die without a problem but still won't chamber the last 3/8 inch of the round. The neck diameter on some of them, but not all, is .003 too big. I thought LC brass is thicker and therefore has less tendancy to stretch. Any ideas or suggestions would be appreciated.

Probably shot in a machine gun... They have loose chambers.

You'll likely need to resize them with a small base die.

Also check that they are still within spec after you resized them. They may have grown in length and you're bottoming out on the bottle neck.

Sent from my Nexus 6 using Tapatalk

 

[ttuttle]

I'm not familiar with a small base die. Who makes them? Are they available at, say, MIdway USA?
Thanks for the quick help.

 

[scap99]

I'm not familiar with a small base die. Who makes them? Are they available at, say, MIdway USA?
Thanks for the quick help.

Yes, Midway should have them.

Most all die makers have one in their lineup.

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[scap99]

http://www.midwayusa.com/s?userSearchQuery=Small+base+308

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[ttuttle]

I hate to appear so helpless. YOur response is appreciated. I have messed with these things all day and I guess I'm just tired.

 

[scap99]

I hate to appear so helpless. YOur response is appreciated. I have messed with these things all day and I guess I'm just tired.

It's all good, and that's the proper spirit of the forum.
You bring in a question, and if we think we know the answer, we chime in.

Also, you can mark your brass with a sharpie marker and try to chamber it to see where it's getting stuck.

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[Dawico]

Check your crimp too. I have seen necks get just enough bend to not chamber properly right at the end if there is too much crimp.

Have you tried chambering a sized, not loaded case?

 

[Eli]

LC brass is 7.62, not .308. What is your Garand chambered in? They aren't the same, a .308 'field' gauge is a 7.62 'go' gauge.

Eli

 

[Texasjack]

Here's a graphic showing the difference between 7.62x51 and .308: http://www.thefirearmblog.com/blog/2015/03/13/graphic-breakdown-of-308-vs-7-62x51/

 

[ttuttle]

That was test #32! I have tried chambering cases after several resizings but the case will not fit the chamber. It is about .006 too big just ahead of the rim. As I mentioned, the neck is also expanded. Apparently the whole case has swelled. I am buying a new die to resize the case. Last time I buy LC brass.

 

[ttuttle]

Garand chamber

LC brass is 7.62, not .308. What is your Garand chambered in? They aren't the same, a .308 'field' gauge is a 7.62 'go' gauge.

Eli

The rifle is a T-type Garand chambered in .308 under a Navy contract. I know there are differences in the the two rounds but I have been told the differences are minor and I have good luck with other 7.62's. LC rounds, possibly out of a machine gun, seems to be the problem.

 

[A.Texas.Yankee]

Probably shot in a machine gun... They have loose chambers.

You'll likely need to resize them with a small base die.

Also check that they are still within spec after you resized them. They may have grown in length and you're bottoming out on the bottle neck.

Sent from my Nexus 6 using Tapatalk

This. Almost all once fired mil brass is from a machine gun that is designed to have more "forgiveness" in the chamber area (much like my pants).

One thing I recommend is getting a case headspace/length gauge.

http://www.amazon.com/Lyman-Reloading-Length-Headspace-Gauge/dp/B002RJURSM

Well, well worth it and saves time once you get the hang of it.

Second thing, if you are getting a new die, check into this small base x-die from RCBS:

http://www.amazon.com/RCBS-X-Die-Small-Base-308/dp/B005KW7PEC

Again worth it as it reduces trimming, for me at least, to every 3rd to 5th load rather than every time. I recommend small base dies for any semi auto (I use SB for my .223/5.56 as well)

Third thing, you *might* need to turn your current resizing die a little further down (maybe 1/4 to 1/2 turn?) because it's possible that your case isn't completely being resized. I've had that issue and with regular brass it didn't matter, but with LC it sure did (even with small base dies).

Hope that helps!

 

[A.Texas.Yankee]

The rifle is a T-type Garand chambered in .308 under a Navy contract. I know there are differences in the the two rounds but I have been told the differences are minor and I have good luck with other 7.62's. LC rounds, possibly out of a machine gun, seems to be the problem.

Also, don't go crazy with these differences between .308 and 7.62 NATO chambers. The difference is the case and round itself, not the chamber.

Most milsurp brass is "thicker walled" brass. That means you have to be careful loading powder in it. It takes less powder because there is less internal volume inside the case for powder to fit. Not a danger issue unless you are getting close to max loads.

Another is you sometimes require a small base die to get it to chamber to start.

With that being said, .308 factory loads are HOTTER than 7.62 NATO (opposite of 5.56 vs .223). You should never shoot .308 factory rounds in a Garand or older military semi autos (like the m14). The hotter rounds can bend the op rod and cause catastrophic failures (and see below more about difference in primers). Now, most "modern" versions of military rifles that are manufactured new and are specifically stamped .308 are ok (the Socom M1 for example). If you are using a converted M1 or older manufactured rifle, stay with 7.62 load information. Most loading manuals have a different section for .308 and 7.62 NATO. There is a reason for that and don't let anyone tell you otherwise. If they were the same, Hornday, Lee, RCBS, etc. would not differentiate them in their manuals.

And lastly...

Primers.

Milsurp brass usually are crimped primers so you might need a primer pocket reaming tool to widen it for seating the new primer.

And then... Due to the nature of a free floating firing pin, 7.62 NATO will tend to have thicker walled primers. Why, you ask? Ever notice the little dimple that's created by the firing pin when you chamber around? Because free floating pin makes a small contact with the primer. If you don't seat your primer deep enough or you have too thin a wall primer, you get what's called a "slam fire" and it's bad because your gun will ignite the round and turn it automatic. Which sounds cool but if that bolt isn't in full battery when the primer is struck, uh-oh.

 

[ttuttle]

Received and understood

Also, don't go crazy with these differences between .308 and 7.62 NATO chambers. The difference is the case and round itself, not the chamber.

Most milsurp brass is "thicker walled" brass. That means you have to be careful loading powder in it. It takes less powder because there is less internal volume inside the case for powder to fit. Not a danger issue unless you are getting close to max loads.

Another is you sometimes require a small base die to get it to chamber to start.

With that being said, .308 factory loads are HOTTER than 7.62 NATO (opposite of 5.56 vs .223). You should never shoot .308 factory rounds in a Garand or older military semi autos (like the m14). The hotter rounds can bend the op rod and cause catastrophic failures (and see below more about difference in primers). Now, most "modern" versions of military rifles that are manufactured new and are specifically stamped .308 are ok (the Socom M1 for example). If you are using a converted M1 or older manufactured rifle, stay with 7.62 load information. Most loading manuals have a different section for .308 and 7.62 NATO. There is a reason for that and don't let anyone tell you otherwise. If they were the same, Hornday, Lee, RCBS, etc. would not differentiate them in their manuals.

And lastly...

Primers.

Milsurp brass usually are crimped primers so you might need a primer pocket reaming tool to widen it for seating the new primer.

And then... Due to the nature of a free floating firing pin, 7.62 NATO will tend to have thicker walled primers. Why, you ask? Ever notice the little dimple that's created by the firing pin when you chamber around? Because free floating pin makes a small contact with the primer. If you don't seat your primer deep enough or you have too thin a wall primer, you get what's called a "slam fire" and it's bad because your gun will ignite the round and turn it automatic. Which sounds cool but if that bolt isn't in full battery when the primer is struck, uh-oh.

You give some good info. I'm not overly concerned about the differences of 308/7.62 but I do observe them. The barrel is stamped .308 Win. The loads I'm making are minimum amount or slightly less so I don't slam the operating rod and bolt. The rifle is very accurate with the lighter loads (38gr Varget) but easier on the moving parts.

 

[ttuttle]

This. Almost all once fired mil brass is from a machine gun that is designed to have more "forgiveness" in the chamber area (much like my pants).

One thing I recommend is getting a case headspace/length gauge.

http://www.amazon.com/Lyman-Reloading-Length-Headspace-Gauge/dp/B002RJURSM

Well, well worth it and saves time once you get the hang of it.

Second thing, if you are getting a new die, check into this small base x-die from RCBS:

http://www.amazon.com/RCBS-X-Die-Small-Base-308/dp/B005KW7PEC

Again worth it as it reduces trimming, for me at least, to every 3rd to 5th load rather than every time. I recommend small base dies for any semi auto (I use SB for my .223/5.56 as well)

Third thing, you *might* need to turn your current resizing die a little further down (maybe 1/4 to 1/2 turn?) because it's possible that your case isn't completely being resized. I've had that issue and with regular brass it didn't matter, but with LC it sure did (even with small base dies).

Hope that helps!

I ordered a small base die yesterday. I already have my resizing die turned down so the shellplate as far as it will go, the way Dillon advises to do it. The brass is hard to get out of the die, I assume because it's oversized. The new die should help. I also had to resize the primer pocket on some of the brass, especially '74 and '86. The '68 brass didn't need resizing. I guess the feds can't make up their mind.

 

[Deavis]

Dillon dies are considered to be small base by Dillon, is that the die you have? I've sized hundreds of thousands of 308 cases from LC with Dillon's sizing die and never needed a small base die from another manufacturer even though I've got one on the shelf.

Are you sure you have the die down far enough and are getting the slack out of the press? A Headspace gage would tell you in less than a second, buying one is a must for rifle loading.

 

[mantawolf]

If you are in McKinney or North texas area, I have a small base for 308 you could try before you receive yours.

 

[ttuttle]

If you are in McKinney or North texas area, I have a small base for 308 you could try before you receive yours.

I appreciate the offer but I live SW of Huntsville, too far away. The one I bought should be here tomorrow.

 

[ttuttle]

Dillon dies are considered to be small base by Dillon, is that the die you have? I've sized hundreds of thousands of 308 cases from LC with Dillon's sizing die and never needed a small base die from another manufacturer even though I've got one on the shelf.

Are you sure you have the die down far enough and are getting the slack out of the press? A Headspace gage would tell you in less than a second, buying one is a must for rifle loading.

I'm using Lee dies until I can get the gist of what I'm doing. I'll pick up a headspace gauge later this month.