Chamber Inserts in a .303 British

lcdrdanr

Looking for comments/opinions regarding a pistol caliber chamber insert in a SMLE MK3 (?) dated 1925 with Lithgow arsenal marks. The old warhorse has been sporterized, stock, receiver sight, front sight, cut down mag, etc and even with the re crowned 25" barrel it still makes a nice handy rifle. Finding inexpensive .303 British has been a no go recently though.

I recently picked up a steel chamber insert shaped identical to a .303 case with the center reamed out to accept .32 S&W, .32 S&W Long, .32 H&R Mag plus .32 ACP (which fits a little deeper in the insert). It fit the chamber tight, I miked the rim and sanded a few thousandths off until the bolt closed easily. Then, tried it with a couple of .32 S&W shorts & Longs, they fired and both exited the barrel although I didn't try for any kind of accuracy. Didn't try a .32 ACP or H&R Mag.

It seems a fun way to keep shooting without the exorbitant price of new .303 ammo (I can cast .32 wadcutters, sized to .312 and load .32 S&W short or long)and I don't think the .32's are gonna lead the barrel but ..................

Any one tried these before or have an opinion or thought about using them? My .303 still has the magazine cutoff installed which makes it easy to load single shot rounds in. I also saw an insert which would accept a 7.62x25 but I wasn't sure about the availability of ammo in that caliber, I understand it is a hotter pistol round though and might make a more useful varmint/pest control round than the .32's. Anyone ever compared a 7.62x25 with a .32 H&R Mag ?

As always, appreciate all input !

charliemeyer007

In general I like the concept of chamber adapters especially for people that don't reload or backpacker's that need to reduce weight.

If you cast bullets why not just load them in your 303 brass. You can load from almost the power of a 22 rim fire almost that of a full tilt load. A pound of Unique will load a lot of shells.

I was 14 when I played with a 303 that was bought for $5. I cast the bullets, reloaded the primers and made the black powder for it. It was respectable load capable of taking game.

rufe-snow

7.62 x 25 is way hotter then the 32 H & R Mag. A lot of the East Bloc surplus on the market. Was made for use in submachine guns, with a muzzle velocity of 1600+ FPS.

If the short light handgun bullets, will stabilize from the rifle barrel? Is a matter you will have to determine yourself, through experimentation?

mmppres

for what 32acp cost around here it is cheaper to buy hornady 303 ammo an shoot that then reload the brass back up

TWalker

I'd reload using cast bullets or round ball. An inexpensive lee loader will do the job. It only neck sizes so the brass will last longer than when full length sizing. Honestly, I think you will be happier with this than using pistol ammo. However, if you can find an chamber adapter that will allow the use of 7.62x39 ammo, that might work OK.

jonk

I wouldn't. Not that it isn't safe, but several reasons.

1. If you're already casting bullets, as others have said, you can just cast a .30 rifle bullet with a reduced load. Plus then it will feed through the action if you DO want a repeater.
2. While nominally the .303 should use a .311" bullet, I have yet to see one that does. If you slug your bore odds are great you will find it is anywhere from .312-.318. A cast bullet needs to be sized at least 1/1000" greater than bore diameter to achieve this. Hopefully you would find that yours is .313" or tighter, so that the excellent Lyman 314299 bullet would work for you, and you could use stock sizing and seating gear. If it is larger than that... well we'd have to have a discussion on what to do next.
3. If you fire undersized lead bullets, you will indeed get leading.
4. Pistol bullets don't carry that much lube. Even at low pressures, assuming a good bullet fit, you might still get leading, depending on the bullet design and how much lube it carries.
5. The rifling in the gun is designed to stabilize a longer bullet. Using a lighter bullet will likely result in poor accuracy.
6. The throat in the gun is likely long, eroded from years of cordite. The pistol bullet jumping out of the adapter is going to fly down the cavern of the throat, slam into the rifling, and deform all to hell, resulting in poor accuracy and possibly leading, as the lube blows off.

What I would do:
1. Slug my bore.
2. Assuming it is .313" or tighter across the grooves, buy a Lyman 314299 mold, some gas checks, and a .314 sizer.
3. Load said projectiles over a reduced load- 16 gr of 2400, 12 gr of unique, 11 gr of Red Dot, 6 gr of Bullseye, or what have you... lots of good cast bullet data on the net. Neck size brass only.
4. Enjoy.

Edit for one more consideration. If you (like me) have a .303 chamber that's a bit generous in the web area just ahead of the rim and are experiencing short case life, a large part of the problem is that on the initial firing, the case expands asymmetrically. To fix this, go to the hardware store, buy a handful of rubber o ring washers. Slide one down onto the case, and try chambering. Keep going until you use the thickest one that will chamber with just slight snug resistance. Now buy a handful in that size and slide over all your brass. This will keep the case centered for the initial firing, ensuring symmetrical expansion.

For that matter, I just leave them on for the life of the brass. Just neck sizing I usually don't bother to tumble brass, as I use a Lee collet die that doesn't scrape over the brass, just squeezes it down from the sides.

lcdrdanr

Appreciate all the comments, it all sounds like I'm okay shooting the pistol ammo in the 303, obviously watching out for squibs or leading.

I have dies and molds for .32 (short, long, and ACP) but none for .303 British, plus I have 6 boxes of .32 S&W long left over from a pistol of that caliber that I no longer have. AND, I carry a .32 ACP for everyday carry so ...................

I haven't seen a 7.62 x 39 insert, not sure if the bullet size would work in a .303 bore but the 7.62 x 25 sounds intriguing although, as mentioned, if I'm gonna cast why not just cast for the .303 which I probably will set up for eventually.

I've heard .303 brass tends to have a short life, like the concept of neck sizing so that's certainly going to be on the agenda.

Thanks for all the comments, really helps us novices

Dan R

machine gun moran

I've tried chamber inserts in an 03A3, but they were a kind of PITA, as the inserts had to be extracted and reloaded for each shot. With a SMLE though, the breech end is wide open and is available for removal of the empty without removal of the insert. But the other potential problems, remain.

I made a 9mm subcaliber insert, from a Suomi SMG barrel, for a 12-ga break-open, that was fun. I ground the muzzle end on an eccentric so the bullet exited on the low side of the 12-ga muzzle, which put the bullet right on at 50 yards.

But the most practical versatility comes from downloading a standard caliber. So now I reload .30-30's with cast bullets at low velocity, and with 85-gr jacketed Tokarev bullets at about 2,000 fps (these were also loaded commercially back in the '20's and '30's, as 'trapper' rounds).

I think I would be tempted to sell the .32 ammo and put the money into .303 brass.

charliemeyer007

I have seen full tilt loaded 303 fail in as few as 3 loading. With normal cast bullet velocities and neck sizing (chamber permitting) brass will go a lot longer especially if you anneal them once in a while. I have worn out primer pockets before case failure, upwards of 50+ firings in several different cartridges.

I set my buddy up with a complete Lyman 310 Tool and dies with bullet and a case FL sizer for his 303 for $40 from a gun show buy some years back. 303 wasn't very popular in the US. I still see stuff around.

The Lee hammer tool will work. Their hand press with regular dies is a better option.

TriumphGuy

.303 Brit brass life depends on what you're firing it in. That gently sloping case body, operating at modest pressure, will last forever in a good chamber with neck sizing. On the other hand, if your chamber is oversize, off-center, out-of-round, has excessive headspace (yes, they can be loose, even headspacing on the rim), or all four, brass will have a short, un-happy life. I had a No. 3 SMLE that would not accept its own reloaded cases without first rotating them around to find the eccentric side. I have a Pattern 14 Enfield with a match-like tight chamber. It will swallow its own fired cases all day with only neck sizing. These rifles were made to fire under horrible conditions with dirty ammo, and they do better than almost any other military bolt gun. Wartime tolerances are beyond loose in some SMLE's, but they are fun.

There is an option if your bore is oversize, even for readily available .311 bullets. Paper patching. Ross Seyfried fiddled with this for years and wrote it up several times in Double Gun Journal. It is not difficult to do, just tedious. He used heavy grade copy paper, helically cut and glued to the O.D. of both lead and jacketed bullets. Claimed it worked great in several calibers.

SoreShoulder

quote:Originally posted by TriumphGuyOn the other hand, if your chamber is oversize, off-center, out-of-round, has excessive headspace (yes, they can be loose, even headspacing on the rim), or all four, brass will have a short, un-happy life.IMHO the extractor can make oversize look a lot like off-center or out-of-round.