.30/06 BSA sporter question

[fat tony]

Does anyone out there know if the chamber throat on one of those commercial BSA sporter made up on an M1917 receiver, calibre .30/06 are generally tight or generous? Thanks in advance for the info. All the best.

PS: I am reasonably certain this is a commercial rifle converted by BSA way back in the 1950's. The other calibres were 8mm Mauser, .270 Winchester, and.303 British.

 

[Eagleye]

The M17 rifle was originally chambered only in 30-06. The way to tell if you have an original barrel or not is to look at the direction of the rifling in the barrel.
Original M17 barrels, chambered in 30-06 had a left-hand twist. If the barrel has been replaced with an aftermarket barrel, the twist is right hand [spirals to the right.]
I have owned several of these rifles over the years, most in 30-06, but a couple that had been changed to other chamberings. The 0riginal Chambers in 30-06
were generous, due to them being used in military action. Any that were converted to other chamberings, would have had the barrel replaced, so chamber dimensions would be
dependent on the reamer used to chamber. Regards, Dave.

 

[fat tony]

It is very doubtful if it is an original bbl, pretty sure it is a BSA commercial bbl. considering all the Brit. inspector and other markings. I' m not planning on selling it as something it is not, my inquiry is reloading related. I heard various things about these rifles including that they used p14 receivers, then others think they used M1917 receivers. The receivers have been modified so it is more difficult to tell what they once were. Thanks for the info! Tony

The M17 rifle was originally chambered only in 30-06. The way to tell if you have an original barrel or not is to look at the direction of the rifling in the barrel.
Original M17 barrels, chambered in 30-06 had a left-hand twist. If the barrel has been replaced with an aftermarket barrel, the twist is right hand [spirals to the right.]
I have owned several of these rifles over the years, most in 30-06, but a couple that had been changed to other chamberings. The 0riginal Chambers in 30-06
were generous, due to them being used in military action. Any that were converted to other chamberings, would have had the barrel replaced, so chamber dimensions would be
dependent on the reamer used to chamber. Regards, Dave.

 

[buckbrush]

they used P 14's for the .303's and the 7mm mags. My .270 is on a m-17.

 

[camster]

I would try a chamber cast or some other means of measuring your chamber/throat.

I've had some pretty good success making a slice in the neck of spent brass, adding the bullet you'll be working with but leave it waaaaaay out. Chambering the dummy should push the bullet back into the case once it engages the lands. Do it a few times, and measure each one. Sometimes the lands "grab" the bullet, and it comes out of the case a bit upon extracting. It's handy data to have for any individual rifle. If you change your bullet choice, do it again with the new bullet.

There are other means of doing it too.

 

[cosmic]

I would be surprised if the rifle didn't sport its original 30-06 barrel. After all, that was the point of utilizing these surplus rifles in a cost effective manner. The rifle would show british proofs as the mods by BSA were done in England. I believe the receivers were re-heat treated by BSA, making proofing a pretty good idea.

 

[Andy]

Is it neck clearance you're trying to determine? Length to the rifling, i.e. freebore + throat?

As mentioned, there are methods that don't require a chamber cast, which almost no-one will do.

Fire a round and measure the diameter of the unsized neck. The chamber neck will be that diameter plus at least 0.001". Typically on a M1917, there will be several thou of neck clearance.

For length to rifling, in a sized, but empty unprimed cartridge seat a long flat-base bullet backwards (nose in), chamber and extract. Measure how much of the bullet remains proud of the neck and that's the approximate length. Typically in a M1917 there is a great deal of distance to the rifling, as much as 0.500" as I've seen.

This assumes an original barrel, but I wouldn't be surprised if you see similar dimensions in this sporter.

Hope that helps.

 

[fat tony]

It was mainly the neck clearance . I should have thought of that, thanks for the reminder.

Is it neck clearance you're trying to determine? Length to the rifling, i.e. freebore + throat?

As mentioned, there are methods that don't require a chamber cast, which almost no-one will do.

Fire a round and measure the diameter of the unsized neck. The chamber neck will be that diameter plus at least 0.001". Typically on a M1917, there will be several thou of neck clearance.

For length to rifling, in a sized, but empty unprimed cartridge seat a long flat-base bullet backwards (nose in), chamber and extract. Measure how much of the bullet remains proud of the neck and that's the approximate length. Typically in a M1917 there is a great deal of distance to the rifling, as much as 0.500" as I've seen.

This assumes an original barrel, but I wouldn't be surprised if you see similar dimensions in this sporter.

Hope that helps.