.303 British in 20" barrel

[brianr23]

I have a Santa Fe Arms "Jungle Carbine" Conversion. I am new to reloading and just finished a day at the range with my new chrono. I just tested one set of handloads and was suprised but not in a good way. Below are my results:

150 grain SP w/ 38gr of H4895
Shot Velocity
1 2129
2 2083
3 2136
4 2023
5 2150
Average: 2104 SD: 52

Not what I expected. By the Hornady 7th ED. with a 25.25" barrel one would expect 2550 fps. I didnt expect to lose that much velocity or have such a high SD. Any opinions, I neck sized the brass and this is the first reload.

I did fire some factory loads and those are listed below for reference. I had a lot of trouble finding velocity info for the shorter barrel in .303 brit:

180 grain Remington Core Lokt
Shot Velocity
1 2314
2 2314
3 2306
4 2302
5 2318
Average: 2311 SD: 7

Remington lists a muzzle velocity of 2460 so I expected a little drop and the SD was great. The 180 grain performed great.

150 grain SP Selliers & Belloit
Shot Velocity
1 2411
2 2428
3 2525
4 2506
5 2433
Average: 2461 SD: 51

Maybe the rifle just doesn't like 150 grain. I don't know the manufactures listed muzzle velocity.

Any tips that you may have would be appreciated.

 

[peterotte]

I am interested in this one too. I have been shy to load down my 303 with 150gr bullets because of a suspicion that my powder will not burn consistently at lower pressure and temperature. Hodgdon lists a pressure of 43,600 CUP with 40grs of H4895 behind a 150gr bullet. The #5 jungle carbine is a pretty strong action, maybe try increasing your load to 40grs and see what happens. (The MkIII could take 45,000 CUP and the #4 & #5 could take 50,000 CUP - not suggesting it 'though).

 

[Curator]

BrianR23:

Your neck-sized brass has more internal capacity than new, unfired factory cases. That can account for some of the lower velocities. Additionally, you don't mention whether or not you applied a crimp. A "factory crimp" can increase velocity and reduce variation.

Neither do you mention the manufacturer of your 150 grain bullets. I have tested both the Remington 180 Core-Lockd and S&B's 150 grain SP bullets and have found them to be quite "soft". They usually obdurate well at standard pressures. It may be that your 150 grain slugs are somewhat under groove diameter and are not slugging up sufficiently to seal off the powder gas. Nearly every one of my Lee Enfields have groove diameters of .313-.315, and do not shoot .311 diameter bullets all that well.

One of the very best commercial bullet for generous bore .303s is the Hornaday 174 grain round nose sopt point bullet. It mikes out to .312 and has a relatively thin jacket. It shoots quite accurately in my Enfields with worn or slightly oversize bores.

 

[peterotte]

A "factory crimp" can increase velocity and reduce variation.

That's a good point Curator. I too have had good results with the Hornady 174 gr RN. It's performance on game was very impressive too - very good penetration with a healthy wound channel all the way through.

On the "crimp" issue, I have done some experimenting with my hornet to get more consistent 'burn' with Li'Gun. The folks say to use a heavy crimp and pistol primers. Well, I sized but did not crimp and got pretty inconsistent 'burn'. The thing is, with H4227, I did not size the cases at all. I used a paper cup arrangement. I tried this with Lil'Gun and the 'burn' was much softer with hugely reduced pressure and velocity. So I began to experiment. I now get the same pressures with no sizing as with sizing and slightly more velocity and seemingly more consistent pressure (from reading the primers). To achieve this, I increased the powder charge and use a cardboard wad and I 'glue' the bullet in place with molten bullet lube.
So, I suggest trying a bullet lube impregnated cardboard wad over the powder - that should seal the bore and raise pressure somewhat. Also, raise the powder charge to Hodgdon's max. (In increments, of course).

 

[Slamfire]

While I have not shot any 150 grain ammo in my Jungle Carbine, I can tell you that shorter barrel will significantly reduce the velocity compared to a 24” barrel. I have some chronograph data with Greek ball in a Jungle Carbine and a No 4 MkII. The velocities in the Jungle carbine are about 150 fps less.

There is not much you can do to increase velocity in a shorty Lee Enfield. You will find that as you increase pressures you shorten the life of your brass. That Lee Enfield is a very springy action and your cases stretch more with higher pressure.

No. 5 Mk 1 Jungle Carbine


174 gr HXP50 Greek Ball
23 Sept 01 T=74°F

Ave Vel = 2351
Std Dev = 26
ES = 96
Low = 2299
High = 2395
N= 13

174 gr Iraqi Ball
23 Sept 01 T=74°F

Ave Vel = 2365
Std Dev = 31
ES = 76
Low = 2325
High = 2401
N = 4



No 4 Mk II

174 Greek Ball ammo
9-May-92 T ≈ 70 °F
Ave Vel = 2488
Std Dev = 12
ES = 27
Low = 2473
High = 2500
N = 5

 

[peterotte]

SlamFire1, do you have any idea what velocity a 'shorty' will achieve with 215gr bullets? The expected 25" barrel velocity would be around 2200fps.

 

[brianr23]

I used the Hornady 150 grain SP (.312") but did not crimp. I don't know why I didn't think to do that, I crimp all my .45 colt reloads and the 150 grain does have a crimping groove. I will crimp the ones I have left to see if that helps. I think I will get some of the 174 grain Hornadys and try them. If I could get my hands on some 215 grain bullets I would love to try them. Midway is always sold out of the woodleighs. I would think in the shorter barrel you would fall below 2000 fps.

 

[Slamfire]

SlamFire1, do you have any idea what velocity a 'shorty' will achieve with 215gr bullets? The expected 25" barrel velocity would be around 2200fps.

It would be only a guess, but I would reduce the velocity by 150 fps. I have never shot anything jacketed that heavy in a Lee Enfield. The cast bullet loads, of 215 grains, that I am firing, I have not chronographed. I expect they are around 1500-1700 fps.

I will say, shooting a Jungle Carbine is like shooting a bomb. There is this huge fireball going off right in front of your face. Bang!