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Case Sizin/Shoulder...I'm doing something wrong...

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/21/2013 at 10:55
garyalarson View Drop Down
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Let me say that I'm new to reloading. But I have loaded about 10 "batches" over the past month and have not run into this problem. I had also shot this exact load before and had not run into this problem.
 
Setup: Lee Challenger Single stage press. Lee .308 Dies and gauges.
Rifle: Remington 700 SPS Varmint 26' Heavy Barrel
Brass: PPU
Bullet: Nosler Custom Competition 155 gr.
Powder: IMR 4895 (42.6gr.)
OAL: 2.800in.
 
Problem: I noticed on the last batch of 50 rounds I reloaded that I had a hard time closing the action on the bolt. Probably 40 of 50 were very tough. Each round fired clean and ejected easily, so opening the bolt was not difficult, only closing it.
 
Troubleshooting: I was thinking it had to do with the shoulder/headspace of the rounds, so measured one round that was difficult to close, and one that was easy. I also took a Remington Corelokt and used that as a baseline. None of the measurements were statistically significant from what I could tell. I use the Lee Trimming tools on each round fired to make sure my starting length if identical.
 
Difference: (Probably not significant, but needed to be said) The only difference I saw between the Core Lokt brass and my PPU reloaded brass was the angle sharpness of the shoulder. The reloaded PPU shoulder was more distinct and sharp where the neck meets the shoulder (I'm assuming from being reloaded in the resizing die it forms that shape). The Corek Lokt angle was the same but where the neck meets the shoulder was more of a smooth/curved line.
 
Any thoughts or feedback would be most appreciated.
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/21/2013 at 11:06
supertool73 View Drop Down
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If you are having a hard time closing the bolt then it sounds like they are to long in the shoulder area.  1 thousandths of an inch can make a difference.

Do you have a good shoulder/headspace measuring tool?  Or are you just putting your caliper on the shoulder and estimating? 

This tool works pretty well for comparing and getting good measurements.  http://www.midwayusa.com/product/479704/hornady-lock-n-load-headspace-gage-5-bushing-set-with-comparator

If you have primers in them and they are not under seated under the rim, that can affect your measurement.  Sometimes a rim might be thicker and that will affect your measurement. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/21/2013 at 12:18
RifleDude View Drop Down
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Hi, Gary --
Get some shoulder bump gages, which allow you to compare case headspace distance between cases with your calipers. I use the ones offered by Sinclair Int'l. Just google shoulder bump gage and you'll find it.

The distinct shoulder line you're seeing is most likely just due to the transition being more clearly refined from fire-forming. Once you fire virgin brass in your chamber, the tremendous pressure from firing defines the shoulder edges as it conforms to your chamber.

I've seen the problem you describe on a couple of occasions. It may actually have nothing to do with case head to shoulder height (headspace length) and instead be due to taper dimensions of your resizing die. If your die was made with the taper dimensions toward the high end of the tolerance and your rifle's chamber is on the small side of the SAAMI tolerance, things can get a little sticky.

If that's the case, then you need slightly more body taper resizing.

IF indeed this is the problem, and if your shellholder is already contacting the bottom of the sizing die when the press ram is fully extended, then one solution to the problem is to take your shell holder to a machine shop that does surface grinding and grind a few .001" (say 0.005" or so) off the top of the shell holder. This will allow just a touch more of the case to enter the die during full press stroke, which will both reduce body taper and bump the case shoulder back a bit. The other option is to grind the same amount off the bottom edge of the die opening. Be very careful here, as you can easily ruin your die if you're not careful. For this reason, I'd grind the shell holder instead, as they're much cheaper.

This all assumes you're already at the limits of press stroke. If not, just screw your sizing die in just a tad and this will fix the problem.

You can also buy small base dies that should fix the problem.

Personally, unless I'm dealing with a very tight chamber on body dimensions, I don't setup my sizing dies to bump the shoulder back much, and I don't FL size. I mainly neck size only. I like to feel tight headspace... as long as it doesn't impair reliable chambering and extraction.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/21/2013 at 13:07
cheaptrick View Drop Down
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Ted beat me to the punch, but I typically FLS using a small base, RCBS die.
Your more than welcome to try mine if your problem persists.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/21/2013 at 22:50
trigger29 View Drop Down
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If the die is JUST contacting the shellholder, sometimes a half turn of the die down will solve it also. You'll feel it get tight on the shellholder, but it'll bump the shoulder a bit more, and take care of the problem in most cases.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/24/2013 at 12:43
garyalarson View Drop Down
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Hey guys. I realized I was NOT resizing the brass. I was using the decapping die and neck sizing, but not resizing the shoulder. Once I started using that die, everything worked fine.
 
Rookie mistake. But like I said when I started this thread. I'm a newbie.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/24/2013 at 15:41
supertool73 View Drop Down
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Good deal, Glad you got it figured out.  Excellent
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/25/2013 at 01:51
8shots View Drop Down
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If you are using brass from your own rifle, that is which has been fireformed in your own rifle chamber, you should be able to only neck size the brass for at least 4-5 reloads. Then you may have to do a full resize again.
Doing only a neck size improves accuracy.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/25/2013 at 13:08
RifleDude View Drop Down
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Ditto what 8 Shots said with regards to neck resizing only fireformed brass. I (as well as precision-minded shooters worldwide) do it all the time. On a hunting rifle that you don't shoot all that often and where you value feeding reliability in field conditions over ultimate precision, FL resizing may still be preferred, however.

Also make sure your brass is really clean, as dirty brass that fits tight in the chamber is more difficult to chamber and extract.
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