Ok, slugged the bore of my Single Seven

[vincecyr]

Measures .312". How big should I size the boolits? .314"?

[Cast_outlaw]

As I understand .313 or .314 are both good

[rintinglen]

.313 works great for me, I have three, all of them measure .312, as does my Sp101.

[high standard 40]

You also need to slug the cylinder throats. Ideally, they will be larger than the groove diameter of the barrel. If so, size your bullets so that a sized bullet can just be pushed through the cylinder throats with thumb pressure.

[BK7saum]

I no longer have a single seven, but it was set up to shoot really well. IIRC, a 0.312 groove, 0.313 or 0.314 cylinder throats and no thread choke. It shot really well, I just didn't shoot it much and traded it. Still have 1k 32 h&r brass and 1100 327 mag brass. Most is new and unfired. I guess I should think about getting a new one to utilize my brass and boolits. lol

[Wheelguns 1961]

I have 2 single sevens and a gp100 in 327. I also have a 32 h&r single 6. They all have .314” throats, and they all shoot .314” bullets very good with no leading.

[alamogunr]

The throats on my Single Seven are .315" The barrel slugs at .312" IIRC. So far have only shot jacketed. I'm hoping to PC boolits to at least .314". Too many projects right now. Probably should have never bought the Single Seven.

[gpidaho]

I measure the cylinder throats with a minus pin gauge and size the bullet at that or plus half a thousandth. Hopefully the bore is smaller than this measurement or you'll need DougGuy to open the throats to prevent leading. Gp

[megasupermagnum]

There is a good chance .313" or .314" will work great. I use all .314" myself. One great thing about 327 federal is the guns all seem consistent, all have similar groove, throat, and twist rates.

[vincecyr]

Measured the cylinder throats. Came in at .314"(one was .3135")

[megasupermagnum]

Measured the cylinder throats. Came in at .314"(one was .3135")

Perfect. Is that with calipers, pin gauge, throat slug, or other? If a .314" bullet is a slip fit in the throat, use that size. If too tight, use .313".

[vincecyr]

Perfect. Is that with calipers, pin gauge, throat slug, or other? If a .314" bullet is a slip fit in the throat, use that size. If too tight, use .313".

Calipers

[megasupermagnum]

Calipers

It is likely a .314" bullet will be ideal. Some like to be more precise than that, but I believe you will have good results without measuring down to the .0001".