How are you getting groove diameters?

[Linepipe]

I am wanting to cast for my 92fs. How are you doing determining the barrel's groove dims? Need to make sure I do this correctly.

Thanks.

[subsonic]

Drive a soft lead slug through the barrel. I like to use hardwood dowel to drive it. If you have 6 grooves, or otherwise can measure the diameter straight across, just measure the slug. If you have 5 grooves or an otherwise uneven number, wrap a thin feeler gauge around the slug and subtract twice the thickness of the feeler gauge.

[69daytona]

I use the oval sinkers with the hole in the middle and a wooden dowel, The sinkers are soft lead and the hole through the center gives it room to collapse easy. Then just mike it.

[uscra112]

Keep in mind that best accuracy and least chance of leading will come from fitting the boolit to the throat, both diameter and form, and not just the groove diameter.

[Linepipe]

Keep in mind that best accuracy and least chance of leading will come from fitting the boolit to the throat, both diameter and form, and not just the groove diameter.

Stupid question: I am not just running a slug through the entire barrel now, got it. I am lost on the process you just laid out. Can you detail it out? :popcorn:

[subsonic]

If you want groove diameter, run your slug through the barrel. If you want throat diameter, you'll have to slug the area just before the rifling where the boolit would reside until iginition. On the semi-autos I've measured, they are very sloppy (read oversize) to help reliability and reduce pressure in case there is a build up from lack of maintenance. On 2 semi-autos, sizing boolits to fit the throat would not allow a completed cartridge to chamber due to the thickness of the brass and chamber dimensions. I sized to the max that would chamber freely. Accuracy sucked. I shot jacketed.

[MtGun44]

DO NOT use a wooden dowel for anything longer than a 6" barrel. You can get away
with it in a pistol, but beware of trying it with a rifle.

Check out the sticky on getting a fractured and jammed wooden dowel out of your
rifle barrel, if you are lucky, with the rifling intact. The best is to use a brass rod or a
1/4" steel rod with a .25 ACP case hammered on as a protective shoe for the end that
goes against the slug. Drive the soft slug flush with a mallet or plastic hammer, then use
the brass tip or brass rod to drive it through the lubricated barrel. A few wraps of tape
on the steel rod will protect the barrel.

Bill

[98Redline]

Bill...you took the words right out of my mouth.

If you are putting lube down the barrel to ease the transition of the slug AND are using a snug fitting wooden dowel you are asking for problems.

As Bill pointed out, especially for rifle calibers, the dowels are too thin and will distort and become lodged in the barrel. Once the oil soaks into the oil it will swell more and you will be seriously in trouble.

Metal rod can be had from any Home Depot, Lowes or other hardware store.

[ole 5 hole group]

I understand that a hardwood dowel could splinter/fracture but you would have to have a super real bad day for that to happen. So far, neither I nor a dozen or so acquaintances using hardwood dowels made from either red oak or mahogany have experienced any problems. I agree that a brass rod would alleviate any concerns of breakage but the chance of a hardwood dowel breaking up within a barrel is about the same as winning the lotto.

[98Redline]

It is much more prevelant with rifles. Longer dowel, smaller diameter.

I don't suspect you would have a problem with a .44 or larger pistol but I might rethink my decision if I were trying to do a .44 carbine.