FGMM .308 Brass

[jfields]

I have been picking up FGMM brass for a while and finally have about 500 pieces that I decided to load some 175 SMK blems that I have had sitting around. This is going to be for an autoloader, but that is neither here nor there. I had the brass cleaned in SS media and annealed a while back and last night I started re-sizing. I keep a Sinclair run out tool around when setting up the dies, and when I checked the first few cases, there was between .03 and .06 of runout on all that I checked. I spent a half an hour cleaning and adjusting the sizing die and could not get it much better.

I then grabbed a piece of brass out of the bin that has the Black Hills .308 brass and sized it and lo and behold it had <.01 runout. I sized three more and they were all the same. The needle was barely moving on the dial.

I went ahead and sized 250 pieces of the Federal and checked several more for runout. they all had at least .03. That sucks. In my experience, that means probably .04 or .05 of runout at the ogive.

The BHA brass is a lot smoother and easier to size. The Federal feels kinda rough going over the expander button.

Any body got any ideas?

Thanks,

-J

 

[rg1911]

I once used FGMM brass with 175-grain Hornady for the 600-yard stage of High Power matches. After two loadings, the primer pockets loosened to the point that I had to throw away the lot. I switched to Lapua and experienced no more problems. This was in an M1A.

My thought is that the FGMM brass is soft enough to deform slightly during the sizing or bullet seating stage.

Richard

 

[FLIGHT762]

Federal brass is thicker than BHA (Winchester) brass. It sounds like your necks are being oversized because of the thicker necks and when you pull the expanding button through, your getting the necks out of whack. You can try lubing the inside of the necks and see if that helps. You could get a spare .308 expander button and polish it down a thousandth or two from the the thickness of your current expander button when using Federal brass, that may help.

Your issue is why some reloaders use bushing dies so they can control the amount of neck sizing and bullet tension on different brass.

 

[jfields]

I had a feeling that the thicker Federal brass was part of the issue. I am starting to think I need bushing dies for all the precision rifle cartridges. I ran in to the same problem with .338 LM brass. I ended up turning the necks, but the correct thing to do would have been to use a bushing die with he correct bushing. I'll lube the necks a little better and make due for now.

Thanks,

J

 

[Bear24]

I use Redding bushing dies mainly for my bolt guns, but as brass lots change so does the need to measure and swap bushings or the necks can get all whacked... Somebody was telling me to use a Lee Collet neck die as it is flexible and not effected by neck thickness, and all neck runout will be fixed regardless of batch thickness.. This doesn't sound correct?

-- I also hesitate as I have blown them up on my Forester-Coax.. Anybody have experience with both?

I'm interested in this as well maybe someone will chime in

 

[FLIGHT762]

I use Redding bushing dies and I also use a lee collet neck sizer. I use a Redding F/L body when I ned to F/L and also use a Lee N/O collet die. The collet die makes very accurate ammo. There is an article where the writer did a test and found that using a body first then the lee N/O collet die created very low runout. I can't find it now, but here's a short blurb on accurate shooter: Tips for Using LEE Collet Dies « Daily Bulletin

You can adjust neck tension by lightly polishing no more than .001" off of the mandrel. Also the article recommends polishing/lightly sanding the interior surfaces of the collet to smooth the necking operation.

 

[FLIGHT762]

I can feel the collet working, it's a light feel right at the end of the up stroke, I can feel it squeeze. Around 25 Ft. #. I don't use a Forster Co Ax, so I don't know how that feels. You obviously over did it. Some reloaders modify the the factory instructions and adjust the collet die to size right at the top of the press stroke just at cam over. It works, I've done it. I found with my single stage press, I can feel the collet squeeze at the top of the stroke. You don't want to smash at the top, bottoming hard on the die. Again, it's a light feel, if you know what to feel for and it works. There'a a lot of info about this on the net.

 

[Markdb0]

Try this.

I have found that polishing the expander ball improves the run out; .3015 & .3025. I have also tried adjusting the when the expander first touches the inside the neck on the pull thru stroke. The thought is to take the play/wobble out of stem during the pull thru process.

 

[scudzuki]

I am sure they produce accurate ammo. But any idea how varying neck wall thickness affects accuracy? If I have to tune neck tension for on type of brass batch by working the mandrel, what happens to the other brass batches?

And again, I blew two of them up on using my Forster Coe-ax. I can't "feel" the collet working. So I had to guess tension was correct. A bit to much pull on the handle and the they destroy themselves.. Well, technically I destroyed them. So how do you get around not being able to feel the collet working?

Thanks to all in advance,

Jt

Quite the opposite; the Lee Collet Die functions independently of neck wall thickness, unlike a bushing, which reduces the I.D. to a size smaller than the O.D. by twice the wall thickness (which varies from case to case). A Lee Collet Die collapses the outside of the neck until the inside of the neck is tight on the mandrel, then the neck springs open a little (.001" if the brass is the proper hardness). The result is every bit as uniform as a bushing and expander, and works the brass less as a bonus.

O.P. I think you are an order of magnitude off in your dimensions; there's no way any modern die is giving you 1/16" (.06") runout.

Joe