Thread: 303/8*57

Strange as it may seem I have a 303 that shot a 4" group at 25 yards, as my son was keen to see what would happen if we cut the barrel a bit shorter we did so, over a year or so, it is now about 12".
With Hyland 150 grain factory 2040 average.
With 213 grain gas check 1028 average
Seeing as how it was a nice rifle to carry and worth a bit of effort I basically rebuilt it as a fully wooded carbine, sweated on scope mounts, bedded and so on and so forth.
Then I slugged the bore, this meant upsetting soft lead projectiles to a larger diameter, which required an upsetting die, a different size for each stage, about 10 different stages.
Finally I found contact with the grove, that is the cut grove in the barrel, the big diameter on the exiting projectile, at 0.323, one of the 8mm sizes, in fact 8*57. The bore diameter is a tight fit, on a standard 303 bullet, hard hammer, be very careful as it might stick type of fit
The fired case from this rifle is quite different from the standard 303, one of which I have and it will shoot a factory spec group at 100 yds, a very good rifle.
What I would like is a few 8*57 American standard loaded cartridges to try, or some 0.323" projectiles.
Can anyone help.

What gr projectiles and how many?

I am not particularly bothered, as this is a proving exercise something suitable for adi 2206h, 6 to 10 is all I want

Can do some 150s or 195s , 150 might be better with 2206h

scotty, thanks, how much, how many, can you email me, noelfj@xtra.co.nz, thanks, Noel Joblin

Greetings @noelfj,
Is the barrel a two or 5 groove or other barrel. .303 rifles are not designed to shoot groove dia projectiles so excess pressures may result. Are you sure of your measurements as .323 sounds awfully large even for a ,303.
GPM.

I said was that I slugged the barrel and found that the projectile need to be 0.323 to mark it, now the question is, what will happen when I fire that size projectile.
This is exactly why I asked for some of that size, to examine the results of firing them.
About safety, the rifle will be fired remotely, and if it blown up then that is that.
I am aware of the benefit of gas blow-by in military weapons, it is a feature that removes debris from the bore, at the expense of performance, so it could be beneficial to use a slightly smaller dia. for actual hunting

Greeting again,
The 5 groove Lee Enfield barrels are around 50% lands and 50% grooves and the loose groove size is designed to allow for expansion of the projectile due to forcing. US barrels are 25% lands or less so projectiles can be close to groove size. The reason I asked about the number of grooves is that the .303 two groove barrels are closer to 80% lands and 20% grooves. This is quite different to the US two groove barrels and is designed to allow more expansion due to forcing while using the standard 174 grain MK VII projectile. Using a groove dia projectile in these barrels will result in high pressure. A few years ago Ruger turned out a run of .303 No 1 rifles. From memory of articles at the time they used a groove dia of .314 or there about coupled with the narrow land US type barrel. Some of these shot poorly due to that combination.
With regard to gas blow by cleaning the bore this may apply to automatic weapons but the reason for the loose groove dia in .303 barrels is to allow for expansion due to forcing in barrels with the wide rugged Enfield lands needed to give decent life with corrosive primers and the hot, erosive cordite propellant.
As an experiment I shot some 150 grain .308 dia projectiles in my two groove barrel. While not as accurate as my usual 174 grain round nose projectiles they were good enough for bush hunting. I have also read of hunters getting decent accuracy with Nosler Partition projectiles in .303 barrels. Your velocity with the Highland 150 grain ammo sounds about right for a 12 inch barrel so I would try some handloads with the 174 grain or 180 grain round nose projectiles before anything else. These seem to be tolerant of the variability in .303 barrels.
Regards Grandpamac.

grandpamac, hellow,
I enjoyed reading your comments, but to add to my earlier statements I would like to explain that the case fired in the 8mm bore smle is different and will not fit into my standard smle and would most likly be the 8*57. There is a record of them being factory chambered just after the first world was or thereabouts, there re a few odd comments of them be chambered here and there through out the world.