Question on RCBS X dies

[dverna]

Almost all my brass is military brass and much of it from machine guns.

When I load 7.62 NATO, I can get rounds that are difficult to chamber. I assume a small base die can address that.

I am planning to feed a few AR’s and two bolt action .223/5.56 guns. Optimum accuracy is of less concern than functionality in all guns. I want to replace my Lee dies with an X die to eliminate case trimming down the road. Should I stay with tge normal X die or get a SB die set?

Thanks for any suggestions.

[Burnt Fingers]

In your case I'd get the small base set.

[Patrick L]

Well, you don't mention problems in .223/5.56, so I assume your Lee dies are doing the job, and I assume your Lee dies are standard, not small base? If this is all correct, I'd go with the standard ones. I use the standard X dies in .223 and .30-06, and I shoot several different bolt guns and semi autos, plus my Remington .30-06 pump. Ammo loaded on standard X dies run smoothly in all of them. I view small base dies as something you buy only if you truly need them, like with your 7.62.

Just my .02

[zubrato]

I’ve never had to use small base dies even resizing machine gun brass, however this is not to say others haven’t had these problems.

I think it boils down to where you get your brass from. Are you buying 7.62nato bulk brass possibly fired from machine guns? If so get the small base. If you’re buying or using commercial brass I think you would be well served with the standard x die.

And yes I have great results with my xdie in 223 and 308. Have yet to see if it has any detrimental effect on neck concentricity but I don’t have those tools to measure it myself.


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[Walks]

I grew up shooting Garand's, never used a small base die for anything but a REM 742, and a REM 700 with a Very tight chamber..
Got a Mini-14 in 1976 and a Colt AR a year later. Always use Standard Lyman or RCBS dies. Never had a chambering problem.
Bought an M-1A in 1988-9. Used Stk RCBS .308 FL dies. No problems.

Friend bought the RCBS X-die set in Small Base about 2008, even with annealing every other loading it seemed the brass cracked in the neck and Stretched a lot, lots of cracked webs. Compared to std FL dies.

I think most chambering problems can be traced to cases that were previously fired in Military Full Auto's.
back in the 1950's-1960's whenever My Dad got .30-06 brass that had been fired in a M1919, he sold it for scrap.

Just my experience. But then I've never been one to burn through ammo as fast as I can. So I probably don't go through enough ammo
To matter.

[BigAlofPa.]

I get that with my 30/30 if i don't make sure i full length resize.

[44magLeo]

Dwell time.
When you resize, do you just in and out?
If you increase the dwell time, time the cases is held in the die, it case won't spring back as much as one just in/out does.
I have a tight chambered 250 Savage That won't chamber cases well without a bit of dwell time. Case up in the die count 3 seconds.
This works with this rifle. It may work with yours.
Leo

[1hole]

I've fired and reloaded a lot of surplus 7.62, .45 ACP, 9MM and .30-06 cases for a long time and have never needed a SB die; I can't see how a 5.56 case could possibly be more difficult.

A good sizing lube properly applied to the lower case and a couple seconds of sizing dwell time in a standard FL sizer die has prevented any sizing problems with any mix of cases I have without using a SB sizer. But .... YMMV.

I know how the X Dies work and, for two reasons, I haven't the slightest desire to buy one.

First, Xs do NOT prevent case stretching in the critical web/head area, they ONLY jam enlongated necks back inside the case shoulder to hide the stretching that's still occurring inside.

Second, the X's instructions first require trimming all cases to the "trim-to" length. IMHO, few cases so trimmed will last long enough to become unsafe from jamming in chamber throats before they should be tossed anyway.

So, what's the point of an X die? They have no place on my loading bench.

[44magLeo]

I have been trying to study RCBS's X dies. From what I see the only difference between the X die a conventional die is there is a short mandrel that fits inside the neck when the cases is fully in the die.
This mandrel is supposed to keep the neck from stretching. It doesn't have anything to do with the neck ID, the rod has a conventional expander button down by the decapping pin.
From what they say this mandrel stops the case body from flowing up into the neck area. I don't see that happening unless the mandrel touches the inside of the case neck. If it does this there won't be enough room to slide the case neck up into the die.
If the mandrel leaves enough room for a case with a .014 neck wall case it won't be enough for a .018 case neck. Or too much space for a .010 neck.
I can't see how it could help any.
The dwell time at this point will be the best option to try. It won't cost anything to try and might fix your problem.
If it doesn't then try a different size die. Do you have anyone near you that loads 308? If so you might get with them and try your problem cases in their die.
All dies are made to a spec but there is a tolerance of the spec. Your die may be a bit on the bigger side of that tolerance. A different die may be on the tighter side of that tolerance.
If that works just getting another size die may be all you need.
Have you tried contacting Lee about this issue. They may sell you just a size die with a tighter tolerance.
Another thought. Lee sells a bulge buster kit that uses a 45 ACP carbide FCD. With the kit you use that die without the crimping stem and just push the case all the way through the die.
The 45ACP head size is very close to the head size of the 308. Most of your excess case expansion occurs just above the case head. Running it through bulge buster may get the stubborn cases to chamber.
Leo