Handloading for the SMLE Mk5 #1 Jungle Carbine

[NORTHOF60]

I get an "ouchie" just thinking of a .303 Epps Improved chamber in a No. 5 MK. 1 - that scalloped knox form doesn't improve strength. Fortunately, standard ammunition should actually show less pressure in the over-sized chamber. IMHO, re-sizing a fire formed cartridge case, even with a standard .303 Brit. neck sizing die won't help case life, due to the reduced body taper of the fired cartridge case being constantly re-worked.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Parashooter]

. . . IMHO, re-sizing a fire formed cartridge case, even with a standard .303 Brit. neck sizing die won't help case life, due to the reduced body taper of the fired cartridge case being constantly re-worked.

Although it's true that a standard FL sizer may reduce body diameter when backed off a bit (less so with a strongly-tapered case like the .303 than less-tapered designs), a proper neck-size-only die is made with enough clearance to avoid the body entirely. In any event, the case life benefit of neck-sizing lies not in any reduction of "working" the case body but in eliminating axial-play of the chambered cartridge ("headspace"), thereby reducing stretch and eventual separation at the web-wall junction.

[NORTHOF60]

Although it's true that a standard FL sizer may reduce body diameter when backed off a bit (less so with a strongly-tapered case like the .303 than less-tapered designs), a proper neck-size-only die is made with enough clearance to avoid the body entirely

I see - that'is what causes the neck not to be concentric to the body. Never used one - always just backed off a FL die. If this rifle is chambered for .303 Epps Improved, a custom FL die will be need.

[Cobbershot]

I did some measurements of several once fired cases and the measurements don’t align with those shown in Cinders book on the Epps Improved case. For this reason I am pretty certain that the chamber in my Mk5 is the result of a worn reamer or “war time tolerances”. I must try to source some Cerrocast to make a casting of the chamber as final confirmation.

The LEE Neck Size Die is a collet style so the only stretch in the case will come from firing, so that should be kept to a minimum.

I’m going back to square 1 with my loadings, as well as re-zeroing at 50m rather than 100m, with accuracy testing of loads being done at 100m. I’m not going to kid myself that this rifle is capable of sub MOA accuracy, but so long as it will hold Minute Of Critter (feral dog, deer etc) I’ll be happy. Frankly, it’s mainly the pleasure of owning and shooting the SMLE Mk5 #1 rifle that appeals to me, but having a useful rifle is also a bonus. I spoke to my mate today about borrowing his 180gr mould (may be a GC mould) to try some heavier projectiles, so that is on the agenda in the near future. Cast projectiles lubed with LEE Alox to minimise leading should be good. I’m having second thoughts about casting them “soft” (Brinell 16)...I may use Lyman #2 Alloy, or even pure Linotype.

Let the fun begin...when family commitments allow.

[browningautorifle]

I’m having second thoughts about casting them “soft” (Brinell 16)...I may use Lyman #2 Alloy, or even pure Linotype.

Don't do it...cast them hard and they'll be fine. Soft won't do. Even with gas checks.