Question on 7.62mm x 51mm vs .303 BRit

[newcastle]

A gentleman i know has offered to build me a precision rifle (for a fee of course) and said he could at a pinch do something in .303 British. I know it sounds a bit mad, but it would enable e to keep calibers minimized. Does anyone have data on the performance of 303 Brit vs 7.62 NATO over 200, 400, 500 + yards? I have to say I am quite intrigued by an updated 'T' rifle in 303.

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[Bindi2]

The choice of match projectiles is limited. Comparing apples to apples they are the same. I would not hesitate about using a 303 in TR out to 1000yds

[enfield303t]

Look up ballistics charts for both and make your decision from that.

Personally a .303 would be a great rifle and out to a thousand yards would take a good bullet and reloading would be interesting but it sure is doable.

There is a thousand yard shoot each spring at Burns Lake BC that started over someone telling his friend you couldn't hit a target at that distance with a .303. That winter they marked out the distance on a lake IIRC, the target was hit and the yearly shoot is the result.

I use (.311) Sierra Match King 174gr HPBT with good accuracy but have never tried anything close to that distance. I am always told that you need a flat base bullet for best performance and maybe you do at long range and should the thousand yard range open where I live I will see how the BT perform.

As mentioned in post #2 the .308 has so many more projectile choices so that is a big vote for using that cal.

[Bruce_in_Oz]

You could cheat a little:

If you are building on an action that was purpose-built for the .303, like a No4 or P-14, it will save a a lot of messing around with mags and bolts.

Then, get your gun plumber to set up a barrel that is actually for .30 cal bullets, but with a .303 chamber. All you need is a smaller pilot and the appropriate throating.

I have such a beast on a No4 action and it works perfectly.

As you will probably not be using surplus Mk7 ball, get it throated for the slinky match bullet of choice; I would go with the Sierra 155 Palmas or 168 Match Kings, (or VLDs if you have deeper pockets)..

Replace the expander ball in your dies with one for ".30" cal and away you go.

A barrel a few inches longer than 26" may just push velocities up to .308-ish levels but there are limits because of the smaller case capacity. You could go with the Epps "improved" .303, but it may cause feeding problems with the mag. Alternately, .30-40 Ackley Improved Krag, or if you want to be daring, 7 x 57 Rimmed. The .284 Winchester, (essentially a short, fat .280 Rem), would fit either action, but you may run into pressure problems with "serious" loads in the No4, and then there is the issue of extractors.

If you have the parts lying around it could be a worthwhile project, but, if starting to build a 1000 yard rifle from scratch, there are a lot better ways to do it. Here in Oz, I have seen a couple of the old single-shot Omark 44s re barreled for the .284 Win; quite impressive.

[newcastle]

I was thinking of using a No.4 action from a rifle with a bent barrel. This is a project rather than a plan. If i really wanted a 100 yard rifle I'd get a remington - hell I'd use my L42 first come to think of it. I appreciate all the advice. keep it coming.

[villiers]

I found that feeding is a lot more reliable with a No. 4 action in .303. And with 7.62, you´ve got the problem (and expense) of finding good, working mags.

[CINDERS]

There will be the wiser ones to follow with knowledge but if you go with a 30/303 as Villiers said mags may be an issue, in my load data program there are 2 types 303 spec's one is 303 Brit and the other 303 SAAMI I do not go near the latter, 308 offers huge projectile selection where as in the 303 your somewhat limited and if you are "bent" on using the action re barrel it with an Armalon Brl which are made to better specs (tighter bore/chrome moly and 1-10TR I think).
The obturation train of thought with FB's is well bantered the Mk VII was FB but the Mk 8Z was BT (for the Vickers I think for long range beaten zone) both used cordite which we do not use anymore choice is yours but sure as eggs ya can only load the weapons action to the specs and to try and drive a projie harder for longer range does not really work in a wartime spec rifle they just were not designed to safely & consistently operate at 50-60,000psi.
And considering the barrel was bent did a M1A1 run over it!

[Thunderbox]

The obturation train of thought with FB's is well bantered the Mk VII was FB but the Mk 8Z was BT (for the Vickers I think for long range beaten zone) both used cordite which we do not use anymore :

8z is a nitro load (the "z") but, of direct relevance to the OP's scheme, the bullet was itself the final pattern of the civilian inter-war "long range match" .303 - the .303 Magnum/Stream Line bullets. These were about the most advanced bullets of their day, and are still probably one of the most researched types of bullet (there were about 15 design increments, and the research group involved Bisley, the Army and the major ammunition manufacturers).

[ssj]

Im not sure what you are trying to achieve? No one cartridge does it all, 308w runs pretty close though.

The no4 is a weak, stretchy action when you start to load it hot, however it can shoot better than a no3 above 500yds if accurised and moderately loaded. So 38gr ADI2208/varget is pretty safe, above 41gr....ho hum, brass stretch and case failures become frequent events.

Bear in mind both are 2 MOA guns and out to 1000yds is a big ask for a 303 IMHO with iron sights and a sling. I do up to 1000yds with a 308w Palma gun that does 1/4inch MOA, but only 600yds with a No4. The no4 can be improved with various bedding tricks, but Ive found it very hard to set up myself. Im still trying to get it much under 2MOA yet approaching 1 MOA is apparently possible, damned if I know how yet.





If you are going to get a new barrel then a hvy one

[Thunderbox]

The no4 is a weak, stretchy action when you start to load it hot,

Really? I'd say that was merely much-repeated myth that simply isn't supported by any evidence.

7.62mm/.308W No4 rifles have been around for decades, and there is no data around to suggest they are in any way inadequate. I had one Envoy accompanied by a log book showing over 9,000 rounds of 155gn match ammo - that one was still tight on a "0" bolt head - and another where the owner had really been stoking it with 168 and 190gn bullets for 1000 yds - ditto on the bolt head.