Reloaders: Can I use a .308 projectile in a .303 rifle?

[Zouave Rifle]

The .303 has a bullet diameter of .311 and the .308 diameter bullets will fit down the barrel when loaded into the .303 British cartridge. Is .003" enough difference in a rifle barrel to cause problems? I'd never try the .311 in the .308, but the smaller bullet might work in the larger bore. Thoughts?

 

[SMLE]

Would it work? Sure. Would it give you good results, probably not. You should always use the right bullet for the job.
Check out www.303british.com for some good info on feeding the Lee Enfield.

 

[Dr. Tad Hussein Winslow]

Would it work? Sure. Would it give you good results, probably not.

That's correct - it may or may not obturate those last 3-4/1,000ths and impart good spin from the rifling. If you have a bunch of .308 bullets lying around, it may be worth a try to load up a batch and check results.

 

[Slamfire]

I recall an article from American Rifleman, back in the eighties, where the author tested a bunch of loads in the 303.

308 bullets in the 303 shot, but not well.

One of the pecular problems with 303's is that most were made under war time conditions and groove diameters vary considerably. (And so reamer profiles.)

So you may be shooting 308 bullets down a 313 bore.

I have a 8mm with a 325 or 327 bore. It will not group better than 6 inches at 100 yards with .323 bullets.

I shot 6.5 * 55 ammo in a French 7.5, to get reloadable brass. I aimed at a berm 25 yards away, and those 6.5 bullets would land anywhere, at least a six foot spread.

 

[Doug b]

Pay close attention to case mouth tension/bullet set back issues.

 

[Mike 56]

Yes it is possible but it might not be accurate. I have seven Mosin Nagant's the bores range from .311 to .314 five of them shoot .308 bullets well. The loads i use are 150 and 165 GR with IMR 4064 a few grains above starting loads with the bullets seated even with the neck. I have had success seating the bullets long 10 thousands off the rifling when using round nose bullets. Slug your bore first you can take apart a 00 buckshot shell and use that to slug your bore the lead is a lot softer than fishing weights and a lot easer to use.

Mike