Reloading the 303 British with 308 bullets.

sn*whunter said: I have for years been reloading the .308 bullets in my 303 British rifles with little or no loss in accuracy or velocity. Best accuracy when using the .308 bullet in my 303 British rifles was .47 inch group at 100 yards, although this particular 303 British rifle had a bore of .309 inch ! Anybody else have any experience in above matters ?

303c*rbine said: A shooting buddy of mine got me into doing the same thing when I ran out of 303 bullets. I take the expander plug out of the .303 full length sizing die and they have enough grip for the .308 bullets. Works good in a pinch when you don't have any of the bigger 303 bullets. If your rifle shoots .308 diameter slugs with any reasonable accuracy then you have a lot of .308 bullets to choose from to blast out of the Brit rifles.:dancingbanana: Learn something new everyday........

d*vid doyle said: lots of p14s with 300 win mag chambers shoot well.

J*hn Y Cannuck said: Lots of 303's have bore diameters running up as far as .318 too. My experiments with the .308 diameter bullets in my 303's have resulted in keyholes at 100 yards, when they hit the paper at all. Best performance is with bullets that fit. Like those I got from Steve Regewell (303british.com) in .313, and .314 diameters. If you got a .47 inch group, check to see if it's one bullet sideways. :D

t*riaq said: Bore diameter or groove diameter? A .308" diameter bullet would be a sliding fit in a .309" bore, wouldn't engage the rifling. Now if the barrel had a .309 groove diameter,a .308 would be OK.

sn*whunter said: Slugging my 303 British showed that the bore diameters varied from .306 for a mint Long Branch, to .309 for a Jungle Carbine.

RR said: Picked up some .311 Vmax 123gr yesterday.Raynor said they were for the 7.62x39 .I'm going to run some through the old martini first and then the Imp 303.Anybody have the software to figure out a load? Rich

W*rkin Man said: Picked up some .311 Vmax 123gr yesterday.Raynor said they were for the 7.62x39 .I'm going to run some through the old martini first and then the Imp 303.Anybody have the software to figure out a load? Rich Hornady lists loads for the 123gr V-max in 303Brit in their manual, up to 3000fps depending on the powder. What power(s) were you thinking of using? AA2015, IMR3031, AA2460, H4895, Viht N135, and RL 12 are the ones they have loads for.

RR said: I have that manual:redface:. but only one of the powders 3031.I think win 748 or hornady benchmark should work (If I work out a load) Rich

t*riaq said: Bore .306" to .309"? Bore diameters that size would be cause for rejection. If these are 5 groove barrels, how are you measuring the slug?

hs4570 said: Have a #4 Longbranch in .303 Epps...3x9 Bushnell 125 gr. Nosler Bal.tip (.308)...47.0 Gr. H335 ...2720..2761..2741 fps 3shots/100yd/0.76 inch....can go to 2900 fps but accuracy was at 2700fps 125 gr. Lapua spzfmj(.309).48.0 gr H335..2857..2896..2914 fps.3 shots/75 yd/0.70 inch. 180 gr. Rem.spzfbase (.308) 46.0gr Rel. 15..2377..2390..2373 fps 3shots/75 yd/0.59 inch 180 rem. 48 gr Rel. 15..2438..2422..2384..3shots/75 yd/0.91 inch 220 gr Win. Silvertip (.308)..43.0 Gr. Imr4350..2036..2021..2012 fps 3shots/75 yd./ 0.53 inch. hs45/70........your mileage may vary

Why n*t? said: I have loaded the 220 gr Sierra Round Nose in several 303 Br rifles and the accuracy was acceptable in all of them. No sub minute groups, but none of them keyholing or shooting four inch groups either. Ted

k*diak1 said: With John Y Canuck on this one my keyholed like a bugger. Put in them .311" babies and it shoots like a dream. Ken

W*rkin Man said: I have that manual:redface:. but only one of the powders 3031.I think win 748 or hornady benchmark should work (If I work out a load) Rich I just checked my Lee manual, 123gr jacketed bullet and Win 748 47.3grs as starting load, but it lists the same for max load, so you might want to try and find another source to verify it.

sn*whunter said: tiriaq, I use a caliber measuring the hard cast .44 lead bullet, which after being hammering gently into the muzzle gives a perfect "cast" of the bore diameter of the 303 British barrel. Then one have both the grove and bore diameter to measure :)

t*riaq said: Yes, but how do you actually measure the bore diameter on a slug from a 5 groove barrel? A measurement for the groove diameter can be obtained by gently rotating the slug between the jaws of the micrometer, but getting a measurement for the bore diameter is different. A slug from a barrel with an even number of grooves is easy to measure for both bore and groove diameter; one from a barrel with an odd number of grooves is different.

s*nray said: "...bore diameters varied from .306...to .309..." There's something wrong with how you're measuring. .303 barrels start at .311".

sn*whunter said: It's like splitting hair :) The calibers normally have a very sharp parts for measuring difficult to reach areas. Well for gor measure, I will re-slug and re-measure the bore diameters of all my 303 British rifles, and post my finding again.

t*riaq said: Thanks. Let us know bore and groove diameters.

sn*whunter said: I am seing your point tiriaq, it is difficult, if not impossible to accurately measure the bore diameter of the five groove, 303 British rifles ? I did re-measure the bore and groove diameter of two, two groove 303 British rifles, a mint Long Branch with groove diameter of .318 and bore diamter of .305-.306, and another well used British made, two groove, 1943, # 4, with a groove diameter of .318 and bore diamter of .308-.309.

t*riaq said: You can get a reading for the 5 groove groove diameter by gently rolling the slug between the jaws. This is delicate and perhaps not as precise as one would like, but can generate a reasonable measurement. I have tried removing the lugs left by the grooves from the slug, and trying the same trick, to attempt to get a bore dimension, but don't really trust the results. I think the best way to get a better sense of bore diameter in a 5 groove is to use plug gauges. The least expensive source I've found is w ww.meyergage.com. I don't have a set for .303, but do for .223 and .30, that I use to dial in a barrel for chambering.




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