Using Lyman Case Length Gauge

[daengmei]

I am reloading brass for a 7.62x51 BM-59 and AR-10. Brass is LC and PPU. After sizing and trimming, the brass still protrudes from the base side of the gauge, very little but it can be seen. It's just enough to see light, if I can find my feeler gauges that is the only I could measure them. Now before getting the Lyman gauge, they did fit into and let the bolt close on both firearms. I just don't understand how they do not quite make the length. I have both a regular RCBS .308 die and also an RCBS small base die. I have set both dies to actually cam over the press, so contact with the shellholder is max. What do I not know?

I did clean the inside of the Lyman gauge with alcohol, as well as the brass.

Also I have some LC primed brass that came this way from Midway. Stands proud as well in the gauge, just a bit. They also will let the bolts close. Factory Winchester loads fall into the gauge down to the shortest length.

Brass rims thicker? I didn't think to check that prior to posting.
Thanks,
Jim

[popper]

Long chamber in your guns - different from the case gauge. Factory ammo is made 'to spec'? Easiest way I know is FL resize without pushing the shoulder back on a case fired in your gun. Measure with feeler gauge at base. Drop in chamber and close/lock the bolt. If it won't close or you have to pogo to get the case out, reset the die to push the shoulder back a couple thou. Retry. You should have ~0.012 max (?) H.S. I'd use the small base die to insure the base is sized all the way. 7.52 NATO has no rim but possibly an extractor tear will be problematic. I had to grind down the die base on mine to get proper H.S. Don't try the holder, it's too hard. Possibly a different brand holder will work.

[daengmei]

I did say rim. Meant base..

[1_Ogre]

With mil brass, eg; LC, I have the Dillon Super Swager to unify the primer pockets. This usually removes that little ridge. I do have some Mil brass from Argentina that has a BIG RIDGE around the primer pocket. I've been told to use a 45det reamer, but not sure about that. That brass is sittin in a cigar box waiting till I figure out a proper way, or it will go into the scrap box

[daengmei]

Will a Forster Coax press have the same type of problem? The shell holder is different, right? I have yet to unbox one and this seems like a good time. Just curious if the shell holder plates give a bit more resize room.

[David2011]

Will a Forster Coax press have the same type of problem? The shell holder is different, right? I have yet to unbox one and this seems like a good time. Just curious if the shell holder plates give a bit more resize room.

If I'm understanding the problem correctly it doesn't sound like a press problem at all. In fact, your description doesn't actually present any problems other than the case heads are extending slightly beyond the end of the gauge. The reason I question that being a problem is that you said the bolt closes on the reloads and the primed LC does the same. Popper is right that your chamber is longer than the case gauge. The case gauge is cut to SAAMI minimum size. Your chamber is larger than minimum. So, if the rounds are chambering properly in YOUR rifle you're OK.

You're already camming over with the die touching the shell holder so no further sizing is possible without shortening the die or shell holder. I have shortened a shell holder and yes, they are very hard but I have a milling machine and carbide tooling but it doesn't sound like your sized cases are too long for your rifle. You do not need .012" clearance between the cartridge and the chamber. As long as the bolt will close without much force the shoulder has been set back enough. When loading for a single bolt action rifle I don't full length resize. I like to feel the bolt just touch the cartridge as it closes. Sizing more than that for a bolt gun just over works the brass leading to early case failure.

Are your reloads fitting the rifle without problems? Is this a break open, bolt action or semi-auto?

[daengmei]

BM-59 is a modified M1 Garand, and the AR-10 is semiauto as well, both 7.62x51/.308. I do get them chambered, they do work. I wanted to understand why the gauge can't be met. Surely the gauge can't be incorrect, but available reloading gear that I have (RCBS) won't quite make it.


I am soon to reload for an AR15, 5.56.....will I see the same thing? Gotta try first I bet you'll say.


Thanks,
Jim

[David2011]

Jim,

I wasn't familiar with the BM-59 designation even though I own a Garand. I had seen the magazine conversions in ads. Yeah, I know what an AR-10 is. I probably read your post 5 times without "AR-10" sinking into my brain. I'm still taking the occasional painkiller after knee surgery so I'll blame that. Yeah, that sounds good.

Measuring cartridges (shoulder datum line) is a challenge without the right tooling so evaluating why the heads are proud is difficult without comparing to another gauge. Do you know anyone else that has a .308 case gauge for comparison? Did you buy it locally where they might have another one on the shelf? It's not impossible for the gauge to be cut too shallow. You definitely need some shoulder setback for autoloaders.

I was thinking about some of my early AR-15 reloading as I wrote my last post. The shell holder I surfaced was for .223. The cases were tight in the chamber even when the die was set to cam over so I cut a few thousandths off the top. (Always work on the cheapest part.) It worked and I haven't had an issue since. I still don't think this is a press issue. One question I've seen raised in the past was the brand of dies and shell holder. Is your shell holder RCBS? My dies and shell holder for .223 are all RCBS but with only one AR-15 at that time it might have been the rifle's chamber that was a little tight. Hard to say, I no longer have that barrel. I have loaded a lot of .223 on my Rock Chucker but for the past 3 years or so it's all been on my Dillon 650. No issues in chambering the ammo made on the Dillon and it's plenty accurate.

Most of my .223 brass was 5.56 NATO surplus brass and it was a total pain to process and prepare for loading. I prepped 3000 pieces plus some range pickups but most of them were commercial brass. It's the most tedious reloading I've done. That is partly (mostly) due to having to prep used military brass and partly to the cartridges and bullets being so small. I primarily load .223, .22-250, 6.5x55 and .30-'06 for rifle and only .223 in volume and the .223 is by far the biggest pain. I hate to think about how much I've spent on trimmers including a Dillon Rapid Trimmer and other items to save money loading those 5.56 cartridges! I also load a lot of handgun cartridges: .22 Hornet, 9mm, .38/.357, .40, .44 Spec/Mag, ,45 ACP and .45 Colt. None of them are as aggravating as the .223 although the Hornet comes close. Shooting it in a single shot pistol, the volume is low, though. If you don't mind buying prepared brass you will probably enjoy loading for the AR-15 a lot more. Maybe you've seen it, sized, trimmed, polished and the primer pockets swaged or reamed. Just add primer, powder and bullet.

Keep us posted!
David

[daengmei]

Might buy another gauge and compare. If different I'll send back one. The one I have now is Lyman. Would you recommend another brand or the same?

[David2011]

I really hate to say anything negative about a company when they have done well for me. There have been complaints about quality control at Lyman in recent years but I have not personally had any issues. Just to be safe, though, you might want to consider L. E. Wilson or anything Sinclair sells for a case gauge (also search for case gage). I hope others will offer their thoughts on the subject of Lyman's QC.

[daengmei]

Can I use a go headspace gauge? Got one somewhere for .308. It should tell me if the Lyman gauge is cut right. Clymer I think it is.

[daengmei]

I used the RCBS press again, this time carefully watching. Even though I set the die touching the shell holder and noticed that it was camming over without the casing, previously I did not see that the casing was not going completely into the die. Cam over without touching the shellholder. I did rotate the shell slightly several times and it finally resized, just too much work. The RCBS Explorer is apparently not robust enough by design and my rifle must have a generous chamber (BM59). I will try using a Herters #3 I just bought. I even told the seller I was thinking of using it to resize .308.

[JWT]

I have found the same issue with 308. Couple moths ago I resized 308 LC brass using an RCBS Rockchucker and RCBS competition dies and shell holder. I was caming over at top of stroke. This 308 was intended for an M1A. After all operations were done, including trimming, I checked cases with the Lyman case length gauge. I found some that were fine and some that were a bit proud. I decided to trust the competition die set and continued loading. I have had no issues with the gun, but I would prefer if the case gauge agreed that the brass was properly sized.