Forster 308 Full Length Sizing Die

[PaulH68]

Hi,

Does the Forster 308 National Match full length resizing die offer any advantages over their standard 308 full length resizing die?

I note that headspace is bumped back .0003". Can anyone explain what benefit this has?


Regards,

Paul

[Alpha1]

Each time you use the die to re size it sets the case shoulder back by .0003" makes it easier to chamber amongst other things.

[rox]

Each time you use the die to re size it sets the case shoulder back by .0003" makes it easier to chamber amongst other things.

I don't think this dies sets the shoulder *back* by 0.0003". To do that it would need to measure the starting position of the shoulder and then magically adjust itself to set the shoulder 0.0003" relative to that variable starting position. That would be a smart die. I also don't think that three ten-thousandths of an inch makes that much difference to ease of chambering.

The literature appears to state that this die will place the shoulder 0.003" (three thousandths, not three ten-thousandths) shorter than the manufacturer's standard .308 full length die. Presumably this is based on standard/crude setup instructions of touching shell-holder plus some arbitrary extra rotation. Any die can be set up to achieve this, but you might need special shell-holders or to grind the shell holder or die-base to get there, so the National Match die might save you the trouble.

Personally, for buttery-smooth chambering (and to satisfy the Jim Hull "rat turn in violin case" sizing philosophy) I use a small base die adjusted to an average of at least 0.0015" less than the actual chamber headspace. This is based on variation of the case shoulder after sizing of +/- 0.0005" so that there's an absolute minimum of 0.001" clearance. Key factors in this are to know your exact headspace dimension (I use my 'smith's incremental headspace gauges when a new barrel is fitted) plus the variation in your sizing process and the clearance you require. It also helps if you can suppress any desire to 'cam-over'.

[rox]

"rat turn in violin case"

Edit: should be "rat turd"!

[Alpha1]

I use a Redding body die with Redding competition shell holders to control the amount the shoulder is set back.

[Alpha1]

The die bumps the shoulder back .003.

Forster 308 National Match Full Length Sizing Die and Bench Rest Seater Die Set
$95.46 EA
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Die Set : Bench Rest® Seater & Full Length Sizing for 308 National Match. No doubt about it: Forster Bench Rest dies set the standard for quality and precision. That's why they're the first choice of some of the world's toughest reloading critics, including members of the US Marines, US Navy Seals, US Army Rangers, US Secret Service, and the US Olympic Shooting Team. This set includes a Full Length Sizing Die and a standard Bench Rest Seating Die, made with the superior manufacturing quality that is a proud Forster tradition. "S" (Standard) Jaws are factory installed and ready for reloading.

*Note: If you are using the Forster Co-Ax Press then a Shell Holder Jaw is not required. If you are using a non-Forster Co-Ax Press then use the Shell Holder recommended by the manufacturer of the press being used.

308 National Match "bumps" or sets back the case shoulder, thereby reducing headspace by .003 From the 308 Win. Case body diameter is the same as the 308 Win. Intended for use in bold-action target rifles.

[Alpha1]

Personally I would not buy this die as I am able to control shoulder bumping using my current set up and utilizing the Shooting Sheds bump and overall length gauges.
In fact if you are not reloading for competitions or bench rest I would invest in a set of standard Lee, RCBS or Lyman dies.
I have a spreadsheet where I collate all the data on shoulder bumping of my cases.

I had a bad experience with a 6.5x55 match barrel that was fitted to a .308 action. I ended up scrapping the rifle. I spent ages working with overall length,s headspace, and shoulder bumping. In the end, I decided the rifle was an accident waiting to happen so I had it chopped and disposed of. So I have spent a fair amount of time working with shoulder bumping etc. But no I still would not buy this die.

[rox]

The die bumps the shoulder back .003.

No it doesn't.

Imagine you have 2 cases with the following head to shoulder-datum measurements:

Case A: 1.634"
Case B: 1.630"

Do you think that after sizing with the National Match die case A will measure 1.631" and case B will measure 1.627" (i.e. each 'bumped' back by 0.003")?
Of course not. The die has no built-in measuring and self-adjustment system.

Below is the description from the product literature.

Where it says "reducing headspace A by .003" from the .308 Win" - "the 308 Win" refers to their 'standard' .308 Win die, order number #005591. It is shown very clearly in the pictures. In a like-for-like setup the National Match die will result in .003" *more* shoulder setback than the Forster standard .308 Win die.

Consider it like this: take the standard .308 Win die, grind 0.003" of the bottom, you essentially have a 'National Match' die.

In other words, if the #005591 standard .308 Win die resulted in placing the shoulder datum at 1.630" (i.e. = SAAMI *chamber* minimum headspace), then the National Match die (set up the same way) would result in the shoulder datum at 1.627" (i.e. = SAAMI *case* minimum head to shoulder-datum). The fact that the difference between these SAAMI dimensions (0.003") matches the difference between the shoulders of these dies is, I suspect, no coincidence.

[Laurie]

Yes. @rox has it right in the previous post.

The thing to remember about 308 Win 'National Match' dies is that they have nothing to do with national level match equipment or ammo quality for today's key precision competition disciplines, but are geared to sizing cases to achieve three objectives - safety, reliable operation, acceptable precision - for one particular rifle in one particular US discipline. The rifle is the US M14 military semi-auto and its BAFTE-compliant M1A civilian equivalent; the discipline US High-Power XTC with most of its stages shot semi-auto rapid fire. Precision is 1-MOA at 600 yards ... and no, that's not easily or cheaply consistently attained with this particular rifle even in much rebuilt match form.

The M14/M1A are very demanding taskmasters, also potentially very dangerous animals. The dangerous bit is that if there is a tad too little shoulder bump / 'actual headspace' the action will lock up enough to drop the firing pin even when the bolt isn't fully in battery resulting in a breach explosion, wrecked rifle and potentially injured shooter. To get these rifles to shoot accurately enough a great deal of gunsmith fettling is needed including minimum SAAMI headspace and very consistent and well made ammo is also needed. A sizer die that doesn't guarantee every case shoulder is bumped back far enough is a BAD THING! The M14 is also notoriously hard on quality brass, so too much clearance not only affects precision adversely, but sees its short case life drop even further. In the days (pre-1980s) when this was the standard US XTC rifle, wealthier competitors didn't handload, they simply bought and fired factory Federal 168gn Gold Medal Match and tossed the cases (which being 'soft' were often not fit for for reloading anyway.)

Then functional reliability under rapid fire is essential, so NM dies are also usually 'small-base' sizing the lower case body down further than with standard dies to ensure easy chambering and maybe help extraction a little too. Personally, I'd never use an S-B type die in a bolt rifle even those with match chambers including 'minimum SAAMI' types'.

The M14/M1A is an historic match arms piece these days as the 223 M16/AR-15 proved so much superior in the High-Power XTC role and rifles are far, far easier to build, tune, and create accurate and functionally reliable ammunition for. I assume that NM dies continue to be in demand given the large number of 'big black rifles' in use in the US these days.

[Alpha1]

Thanks Laurie.