.303 British bullet diameter?

[TrxR]

Whats the best way to figure out what diameter bullet I need for reloading my .303 british? Right now Im shooting Federal blue boxed 180 grainers that it seem to like.

Thanks

 

[FergusBailey]

303 bullet diameter is .311

 

[BigDMT]

303 bullet diameter is .311

Yep, 0.311".

I'm not a fan of the round because the brass is the worst there is (too thin), but have handloaded it for my stepfathers Springfield rifle. Had good luck with accuracy using the 150gr Sierra GameKings.

 

[ChrisNZ]

If you're going to be reloading for any of the British SMLE/No.4 rifles, BE CAREFUL.
Remember these are a somewhat flexible rear-locking action that is not nice on brass. If you're using anything like full loads, FL resizing is mandatory else you'll get chambering issues.

I will only shoot very moderate loads in mine and I file a little notch on the rim every time I reload. I discard them after three reloads. Normal rules don't necessarily apply with these actions. The last thing you want is a case separation as the gas containment ain't good...

Chris-NZ

 

[2506]

To really get the proper diameter bullet for your rifle you need to slug the bore. Get you some .315 diameter muzzle loader lead balls or find a fishing sinker at least .314 in diameter. Drop it into the chamber. With the bolt removed start the lead slug into the bore using a metal or brass rod that you can hammer on. After it has been started drop some 6 inch long hard wood dowel rod pieces that are just small enough in diameter to fit through the bore one at a time and then use your metal rod to tap on them so it pushes the slug through the bore. Let the slug drop on to a soft cloth like a waded up towel or T-shirt. Measure between the high spots which are your grooves in the bore. This will give you the proper diameter bullet you should use. These old war horses have a variable size bore made by war time production and worn reamers or by lots of use. I have one that looked unissued and it likes .311 diameter bullets but I have another one that looks like it has a great bore but it prefers .312 diameter Hornady 174 gr RNSP bullets. If you want to get better case life I have found that by using the cases that have only been shot in one particular rifle and only part sizing, neck sizing with a full length sizer by just sizing the case enough as to just slightly bump the shoulder works great and makes for greater accuracy. But do watch for any signs of a bright ring around the web of the cases. It is best to bend you a paper clip with a little hook end and slip it into the case and use it to feel for a thinning on the inside of the case at the web. These rifles purposely have sloppy chambers. It is so that in the mud blood and trash of a battle field when ammo gets dirty they will still work. It lets the cases stretch a lot. Don't try to hot rod this round in these old rifles. They work best with 174 to 180 gr bullets at around 2300 fps and IMR 4064 seems to be a great powder.

 

[BigDMT]

To really get the proper diameter bullet for your rifle you need to slug the bore. Get you some .315 diameter muzzle loader lead balls or find a fishing sinker at least .314 in diameter. Drop it into the chamber. With the bolt removed start the lead slug into the bore using a metal or brass rod that you can hammer on. After it has been started drop some 6 inch long hard wood dowel rod pieces that are just small enough in diameter to fit through the bore one at a time and then use your metal rod to tap on them so it pushes the slug through the bore. Let the slug drop on to a soft cloth like a waded up towel or T-shirt. Measure between the high spots which are your grooves in the bore. This will give you the proper diameter bullet you should use. These old war horses have a variable size bore made by war time production and worn reamers or by lots of use. I have one that looked unissued and it likes .311 diameter bullets but I have another one that looks like it has a great bore but it prefers .312 diameter Hornady 174 gr RNSP bullets. If you want to get better case life I have found that by using the cases that have only been shot in one particular rifle and only part sizing, neck sizing with a full length sizer by just sizing the case enough as to just slightly bump the shoulder works great and makes for greater accuracy. But do watch for any signs of a bright ring around the web of the cases. It is best to bend you a paper clip with a little hook end and slip it into the case and use it to feel for a thinning on the inside of the case at the web. These rifles purposely have sloppy chambers. It is so that in the mud blood and trash of a battle field when ammo gets dirty they will still work. It lets the cases stretch a lot. Don't try to hot rod this round in these old rifles. They work best with 174 to 180 gr bullets at around 2300 fps and IMR 4064 seems to be a great powder.

Wow. That seems like a lot of work for not much if any gain.

Those old war rifle barrel bores are so bad that you have to keep your expectations for accuracy a lot lower than you would for a modern bolt action rifle.

Headspacing was so bad in my stepfathers rifle that the shoulder on new brass would low forward over 1/8"!!! So I fire formed the cases with mild powder charges before I load tested any further because that amount of headspace was far to dangerous to mess with using normal pressures.

After many load tests resulting in 4"-8" three shot groups at 100 yards, we finally found a load that shot under 1.5". So being that it would only ever be a shorter rangte hunting rifle, we happily accepted that level of accuracy before we wasted more time and bullets.

 

[ChrisNZ]

Apparently, the mil armourer's definition of "accurate" for a No.4 was 2" @ 100yds.
If you can get 1.5", I'd wouldn't be wasting time looking for better

Chris-NZ

 

[BigDMT]

Apparently, the mil armourer's definition of "accurate" for a No.4 was 2" @ 100yds.
If you can get 1.5", I'd wouldn't be wasting time looking for better

Chris-NZ

That's exactly what my thoughts were and that's why I stopped there. From what I was initially seeing for accuracy, i was actually very surprised to see a group that small.

Can't remember off the top of my head, but I know I used 150gr Sierra GameKings, and I believe it was a charge of imr 4895 that was "40-some" grains. Would have to look it up in my log book to be sure

 

[jonbearman]

You can correct the headspace by getting different bolt heads which should still be around.

 

[GarethMarijt]

You can correct the headspace by getting different bolt heads which should still be around.

There is some information on this on this (http://www.303british.com/id28.html) site.

Gareth

 

[moorepower]

I have read of folks using a thin oring to hold the brass back on fire forming. These chambers were designed to feed flawlessly and close the bolt even with bits of sand in the chamber, and not target shooting. The 303 Epps reamer is available to rent, and will have a shoulder after fire forming if accuracy improvement is really desired.