View Full Version : Pin Guages, Sand Cut Carriers and L. Shoulders

September 23, 2001, 15:25

Since the permanent funds are coming, I have earmarked some money for two complete sand cut carrier/bolt assemblies to place into my CAI FrankenFals cause they look cool.

I noticed a post awhile back by G. Jeter in which he described the use of pin guages. I placed the address of MSC Industrial supply into favorites and was looking at the guages today.

I take it they are used in the same manner as a guage tool with the different diameters along the length of the tool? Just slip them in hole and proceed to play with Go/No-Go guages? If so what are most common choices? I have not been able to find address for Spiro-Fab where they listed ALL locking shoulder sizes.

Your help is appreciated. Thanks.

September 23, 2001, 15:35
for some reason the spiral fab site isnt wanting to come up, could just be a busy server for now but here is the address.http://members.nbci.com/_XMCM/spiralfab/

September 23, 2001, 18:01
I only have .256, .258, .260, and .262

That's all I've needed on the few rifles I've assembled.

I'd like to have .264 too. I gotta remember to order that with my next MSC order. You think TAPCO is bad. Wait until MSC figures out what you are into, and starts sending you specialty catalogs!

The pin gages just slide through the lockning shoulder hole.

When you order, you have to tell them whether you want "plus" gages or "minus" gages. It matters not. But it is advisable to stick with one or the other for the set you order.

I have observed a small discrepancy while using the MSC pin-gage method. If the pin gage allows the bolt to just close on a 1.632 headspace gage, and I install a locking shoulder of the same nominal diameter as the pin gage, the rifle's headspace will end up .001 LESS (i.e. 1.631).

I have measured the diameter of the pin gages. My caliper confirms that the number printed on the gage is accurate.


A cut-and-paste from the Spiral Fab site is at http://www.l1a1.com/cgi-bin/forums/ultimatebb.cgi?ubb=get_topic&f=3&t=002538

See also http://www.l1a1.com/cgi-bin/forums/ultimatebb.cgi?ubb=get_topic&f=3&t=000874

September 23, 2001, 19:37
Gary, Lostone, thanks for the data. I did a print screen to save it. Thanks again.

September 24, 2001, 07:01
The info you have been given works.
My only difference is that I am a WECSOG and I buy new untested receivers. If you stick with the proven, tested receivers, disregaurd my next statement.

I have tried several new makers. I have found that a little more variety in pin gages is needed. I have used as small as .254 and as large as .271 in locking shoulders. If you stick with Entreprise, IMBEL, or DSA you should be fine with the advice given.
I am not a gunsmith, and I learn on each build. I have bought a few receivers that were several thousandths from a .262 norm. But only with the new guys receivers. I need just a couple more pin gages than Gary's advice, but the 3m masking tape method will work even in a pinch (see gunplumbers guide). Gary gives good advice, but I stray...