Redding Dies and SAAMI Tolerance ?

[Bert]

Hi All,

Please reference Maximum Cartridge / Minimum Chamber specs at http://www.saami.org/PubResources/CC_Dr ... 0Ruger.pdf and in particular just above the web (.3759") and just below the shoulder (.3615").

My Redding Body Die is running .375 - .376" & .360 - .361" (The die is adjusted to shell-holder contact + 1/3 - 1/2 turn, has a pronounced "cam-over").

My problem is this - My Howa 1500 chamber seems to be pretty much on SAMMI chamber spec (judging from .376" / .362" fire-formed cases). So, too often, I am getting cartridges stuck on *feeding* one at a time , and also from the magazine (extraction after firing is not a problem).

Most of my problems with "sticky" cases feeding happen 5-6 rounds in, seemingly as the gun warms up a bit.

For comparison, Hornady factory loads are running ~ .373" & .357 (i.e. ~.003" smaller), and feed / extract fine. Additionally, virgin RP brass (250+ rounds) has fed fine. Problem seems to be with my resized brass.

My question is this - anyone else using the Redding Body Die (or the FL Die), and what dimensions are you getting ?

Any other ideas ?

Thanks, Bert

[Ol` Joe]

Brass work hardens and getting a die to bring it to a specific size is a gamble. When a die resizes your case it knocks it down about 0.002" or so under the desired point. Then when the case is extracted from the die the brass "springs back" and hopefully stops near the proper dimension. The more you load the cases, pressures you load to, and the amount of expansion your chamber allows compared to the reduction your die does will affect the cases and work harden them. Hard brass wont resize as well as we want, and old brass will come out of a die with a different geometry then new.

[Bert]

I am having problems with once-fired brass (purchased virgin from Midway, then fired in my gun ), and some twice fired. All (~ 300 total )are resizing to the same size as reported above.

But I guess in regards to your point, I am asking "what is the desired point?" that folks are getting on their Redding dies (are all bored within .0009 of SAMMI chamber spec...for me, it is a bit large, and a tight tolerance (generally less than .0015" between case size and chamber)?

I am not having a problem with consistency.

B.

[Hedge]

My Redding body die is squeezing them down to .3755 and .3511 on average. Hard to get the same spot for reading without a ball type micrometer. Not having feed problems. Like ol' Joe says...depends on how worked the brass is.

[Bert]

Thanks, Hedge,

That is a helpful comparison. Below the shoulder, your die seems to be running .010" smaller (and what I had expected in mine). Looks like down near the web, it is pretty much the same.

Out of curiosity, what are you getting right on the shoulder (the reference & headspace diminsion) ? I am getting avg .3590"

I will anneal some and see if that helps, but most of these are only fired once and still seem pretty soft (Remington Peters headstamp) . I hope that is not the problem so early in the life of these cases (I was hoping for at least 2-3 reloads before annealing)

Bert

[Hedge]

Bert -

I'm getting .3605 & .330 at the two data points. Just about chamber spec. I believe my chamber is a tight one. Couldn't load some factory Hornady. Hornady measured the cases and found them to be factory max.

I'm using Winchester cases and I've gotten about 12 reloads before annealing.

[Bert]

Thanks Hedge,

BTW, I did select a sample of once fired (form-fired in my Howa) cases today, annealed several (made a cool fixed geometry jig for my pinpoint torch on my multi-axis drill press).

I then re-sized the whole group (annealed and un-annealed). There were no differences in the final measurements (all were about .0029" under SAMI *chamber* spec, and ~.0020" or less under cartridge spec). So, work-hardening does not seem to be a factor (yet).

Looks like I have tight chamber *and* big dies.

I'll call Redding for advice this week.

With this set of dies, I will certainly have to do a thorough dimensional inspection on every single cartridge for my Howa 1500......

I have a Thompson Encore that I will set up this week, and see how it does.

Bert

[Hedge]

You're welcome, Bert.

Yup, sounds like the dies need to be tooled tighter.

Let me know what Redding says.

[Jim White]

If ya' can't squeeze the brass down far enough Redding does make off-set shell holder that may workout for you.

HTH

[Bert]

If ya' can't squeeze the brass down far enough Redding does make off-set shell holder that may workout for you.

HTH

Jim,

are you talking about the Competition Shell Holder set ?

I have a set of those, that bump the shoulder up to another .010"; it does give me about an additional .0005" in the dimension that seems to be hanging up on me. My shoulder headspace dimensions do not look not too bad, actually, but I will definitely add this to the list of questions to ask Redding .

Thanks,

Bert

[Jim White]

Thats the one. If you need more than .010 then you may have to get STD shell holder a get it turned down. One thing to be awre of if you go that route, is the shell holder will be a tad weaker because of the removed metal. Make sure you lube the cases real good, other wise it could break and be left with a stuck case.

[Bert]

All,

I did speak with Redding tech support, who were very helpful.

Just below the shoulder, the body die is cut to .3570, and assumes .001 -.002 spring-back (cartridge should be resized to nominally .3590, which is what I get).

I will add that they commented on the fact that some re-sized cartridges can continue to spring-back a bit (maybe .001") over a few months (my reloads were ~6 months old). If you have a tight chamber like I do, check your dimensions before you go out.

They advised against adjusting for "cam-over" on this one, as it can deform the shoulder to a possibly a larger diameter.

They did offer to swap out the die or help me look at more advanced solutions, but I declined their generous offer, and will attempt improve my own QA now that I have a better understanding of the tight tolerances I have with this die / chamber combination.

It's a bit more challenging, but I am happy, especially with a $400 gun running .6 MOA on Dogtown 34's.

I did also try the Thompson Encore, quickly got it sub-MOA with some 40 grain V-Max, and drilled a few clays edge-on at 200 yds. The chamber cut is a bit more forgiving too, so my current set of dies work fine for it.

So, the final answer to my question, is yes, Bert, Redding .204 Ruger body dies are indeed and intentionally cut very close to SAAMI maximum cartridge specifications (and this is not necessarily bad).