Shooting an Oversized Boolit

[Coote]

I have a two-groove No 4 Lee Enfield .303 Br that has an oversized barrel. I slugged the barrel and found that the land diameter is around .305", and the groove diameter is .321"

So I am going to need a relatively big projectile. From time to time I may have a good stock of cartridges loaded up for this rifle. At this stage all my cartridges are likely to have soft boolits and relatively slow loads.

Now here is my question. What if I.... or one of my relatives or shooting buddies.... gets hold of some of this ammo and goes to shoot it in another rifle (presuming that it chambers easily). Does the shooting of these large projectiles in a 'standard' bore create any significant danger? (Remembering that these are soft boolits with a gentle charge).

I'd be interested to read your thoughts on this one. Thanks in advance.... Coote.

[geargnasher]

So the grooves are .008" deep???

Gear

[Coote]

Unless my slugging technique is all wrong.... yes, the grooves are .008" deep.

I probably would save myself some hassles if I simply got another rifle to play with. But this one is special to me.

[geargnasher]

So, provided you have adequate loaded chamber neck clearance shoot an 8mm (typically casts somewhere around .323") boolit through it. Consider using the Lee Collet Sizing die for the .303, you can adjust the amount that the die sizes the neck, so once your brass is fireformed you can dial in the exact amount of neck tension you need.

Making a chamber cast or impact slug of the chamber and throat would be helpful here.

Gear

[Coote]

Thanks Gear. I think that is a good option. But what if someone inadvertently picks up some of this bigger ammo and tries to shoot it in a rifle with a standard barrel.... am I creating a hazard by having .303 cartridges on hand that are loaded with 8mm boolits?

[MtGun44]

Please be sure your slugging is correct. Are you using a micrometer or a caliper
to measure?

I'm not saying this is impossible, but it is at least pretty improbable, and whenever
I come up with something like this, I redo the measurement, because you may not
make mistakes, but I sure do.

Bill

[geargnasher]

Check your chamber neck size before worrying too much about other guns.

Gear

[Coote]

Thanks for the comments.

I will re-check thanks. I use a micrometer. While my measurements of the slug are probably right, perhaps I distorted the slug somehow.

As to the chamber neck size, is a fired case a good enough indication of size? I can fit a paper patched boolit of about the size in question into the unsized case. I guess the correct way to measure this is to make a specific slug of the neck area. Thanks... I will work on it.

[geargnasher]

Do a quick search here for "chamber+slug" and see what you get, the making of one has been detailed a few times.

A fired case, provided it was a reasonably powerful load that was fired in it, is also a good indicator of largest safe boolit diameter. Remove any trace of crimp before measuring. You can always load a dummy round with a .323-4" boolit and wrap one layer of cellophane tape around the neck and see if it will still chamber.

Gear

[Larry Gibson]

I wouldn't be concerned at all about cast bullet loads with .321 - .323 diameter bullets being fired in other smaller groove sized SMLEs. Couple things to remember is that the cast bullet is soft and will be "sized" down in one bearing length. This will occur long before the peak psi is reached. Second is your loads probably won't chamber in other SMLEs, especially if the fire formed cases are neck sized.

Lastly consider the American loaded 8x57 ammo (Remington and Winchester). It is loaded with .323 diameter jacketed bullets of 170 gr weight. It is also loaded down so if fired in the older .318 bores it will still be safe psi wise. Your cast bullets will size down with a lot less psi increase.

Besides, if you want to dance with the old girl you got to buy her a dress that fits.

Larry Gibson

[Sonnypie]

Besides, if you want to dance with the old girl you got to buy her a dress that fits.

Larry Gibson

Now that right there, folks...
THAT is a sticky!
What a Gem! :lol:

[Coote]

Thanks Larry, that is what I instinctively felt about the situation. However my experience is limited and I have been wrong before.

I see Lee have a mould for a 170 grain projectile that is .324" diameter. I might have to wait for a wee while before I get it though, as I've spent my allowance on other related stuff.

I should try to get some reliable measurements though. It would at least be interesting to see how everything relates.

Thanks for all the comments so far... Coote.

[chboats]

Coote - shooting a 324 boolit in your rifle should not be a problem if the chamber neck is large enough to chamber a round with that big of boolit. I have an Argentine 7.65 carbine that the throat is .325 and tapers to a grove at the muzzle of .316 and looks like 150 grit sand paper. I shoot .325 boolits in it. I had the trim the case neck thickness to .011 in order to chamber the rounds. I don't even try to load anything that could be called high velocity, 16gr of 2400 is about the hottest thing I load. These rounds will not chamber in a rifle unless the throat is shot out like this one is.

I started out with smaller boolits .316 but the accuracy was 6" at 50 yards. The larger the boolit the better the accuracy got until it filled the throat. IF I do my part it will shoot 2.5" at 100 yards with the original sights. My experence with this rifle says load to fit the throat.

Carl

[303Guy]

The groove depth sounds about right. One of my two-grooves has a .304 bore and a .318 groove. A digital caliper is pretty accurate with practice.

[milprileb]

Lots of solutions to consider and great advice to run with.

I would submit, in the interests of safety, just label your ammo
unsafe for use in 303 caliber rifles other than the serial number
of yours.

I say this cause its no bother to label boxes of ammo and if you croak,
relatives will be well warned before shooting the stuff.

I reform a lot of brass and I keep ammo and empty brass in containers
well marked this stuff is reformed and not 3006 as head states. I do this
so Murphy does not strike my son if I am long gone some day.

[303Guy]

On the neck clearance thing, bearing in mind that some things I do and say are controversial, I load my paper patched boolits to be a tight/snug fit that requires assistance from the press to finish the seating in an unsized neck. These chamber with a slight resistance but that's because the neck area of the throat is irregular. My loads are nowhere near max and primer flattening indicates moderate pressures (there is no primer back-out). Common wisdon says there should be clearance to release the boolit. I'm saying that is the boolit is a squeeze fit in the throat/bore then what's the difference - with paper patched boolits anyway? Perhaps in reality there is a small clearance! Anyway, one needs to temper what I say with one's own sense of what's right.

[Coote]

All good comments thanks... much appreciated.

Last night I made up some dummy rounds with soft lead boolits so I could have a go at getting some decent throat/rifling slugs for a couple of Lee Enfields.

http://i61.photobucket.com/albums/h71/kiwicoote/July%202011%20Onwards/ChamberSlugs05Nov11.jpg

I used these slugs in my oversized short No 4, and in a No 3 that I hope to shoot some real boolits in.

I'd already driven a soft lead ball into my short No 4 barrel and the measurements indicated that my bore was on the big side. These latest slugs reconfirmed this, although my measurements were slightly different.... perhaps because the ball was driven further into the barrel.

The slugs that came from the No 4 barrel appear to taper toward the front. Near the front the lands diameter is around .307". Nearer the case, the lands diameter is close to .313"

For the same rifle, the groove diameter is a fairly constant .322", and that is fairly big. But possibly just right for shooting a lead projectile cast in an 8mm mould.

The narrow band immediately in front of the case is not easy to measure because of its narrowness, but it is about .324" in diameter.

The slugs from the No 3 show no real signs of rifling, although the rifle does appear to have decent set of five grooves when I look through the barrel. The front end of the slug measures around .314", and the rear end is closer to .320". The collar of lead immediately in front of the case measures around .333" in diameter.

I'd be interested to read any comments you might have about my slugging results. I'm particularly intrigued by the apparent taper. And of course I'm a little dismayed to have two Lee Enfields that I love that don't seem to have 'standard' bores where I can use a standard mould. But maybe I can... I probably need to stop being theoretical and just shoot some ammo to see what happens.

I have a Lee C312 185 1R mould speeding its way to me now. I'd love this to make usable boolits for my No 3.

Best wishes from NZ on a cool Sunday morning..... Coote.

[303Guy]

That taper on the two-groove is the throat. It has no leade as such, just a 1.5 degree taper throat.

The riling on that five-groove seems pretty worn, just like my cavalry carbine bore. My pig gun bore is just plain rust damaged yet with paper patch boolits, both guns shoot pretty well. The pic below shows a pig gun boolit. That one was patched to .325. The carbine takes the same casting but with thinner paper patched to .318.

I've just done a test to see exactly how well or otherwise my theory of tight necks works out. I made up a oversized patched boolit using a slightly smaller diameter casting and thicker paper as in printer paper. I had to expand the neck on a fired case just ever so slightly to get the boolit to enter and had to seat it by press and then it was firm. The loaded case neck contacted the chamber walls on chambering anf had to be pushed in with the camming action of the bolt. The charge was 7.5gr Trail Boss with cotton filler. The primer hardly shows the presence of powder in the case.

http://i388.photobucket.com/albums/oo327/303Guy/PRINTERPAPERTIGHTNECKTB7gr206gr014.jpg

This was with paper patching which does have compressibility!

[Coote]

That is useful information thanks 303Guy. There is a strong possibility that I will be shooting paper patched boolits in .303s, so I'm grateful for all this good data.

I have yet to get more familiar with the concepts of leade and throat etc. I can understand the theory behind them, but in practical terms I need to learn the specific details of each of my rifles. I've been shooting Lee Enfields successfully for over forty years, but I reckon I'm now on a journey where I will be learning a heap more about them. I recently scrounged about 25 kg of wheel weights which yielded maybe 16 kg of clean ingots (I had to weed out quite a few zinc and steel weights and other odds and ends). I have finally progressed to the casting phase of my evolution.

I want to get the five-groove running without patches though as this one has a moderator fitted to it and I would be surprised if the patching didn't get clogged in the moderator.

[303Guy]

I did another tight necked test. Again expanding the neck to get the oversized boolit in, this time with thinner paper and a larger and a little harder casting. Also the powder charge was 34.8gr W748 under a 205gr boolit. Pressure seems mild to moderate. It is a moderate load.

http://i388.photobucket.com/albums/oo327/303Guy/tightneckW748205gr003.jpg

DO NOT ATTEMPT TIGHT NECKS WITH JACKETED BULLETS!

[Coote]

Am I missing something.... or is that a picture of the primer?

[303Guy]

Yes, it's the primer. Notice how rounded it is. Those primers will flatten a fair amount when pressure approaches SAAMI levels. I posted that just to illustrate what I mean by mild to moderate pressure.