Reloading .303 British - Gas checked bullets

Gas checked bullets

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Category: Reloading
Forum Name: Reloading .303 British
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Topic: Gas checked bullets

Posted By: martini1215
Subject: Gas checked bullets
Date Posted: December 17 2023 at 4:45am

Morning gents.

I do reload a lot of ammo of various calibres including 303 British.

When I bought a lot of un needed ammo and bullets from a friend who packed in a gunsmithing business he included a wide and varied selection of cast , gas checked bullets and suggested using them in short range practice. I was wondering if there is any literature online giving guidance using these for reloading?

I have slugged my barrel and it is .311 , as its a newish barrel I thought this about right.

The bullets vary in weight and in calibre .311 through to .316 and weights up to 182 gr.

The only information he have me was keep them subsonic and suggested Unique as propellant.

I have a lee neck expander to open the case neck before bullet insertion I believe.

Many thanks for any pointers in the right direction.

Replies:

Posted By: HammerDown
Date Posted: December 19 2023 at 7:32pm

There is 303 British load data for cast lead bullets here:

"The Complete Guide To Handloading", Sharpe 1937.

The document is free to download and the 303 data is on page 382. Unique is one of the powders listed. Lots of useful information for reduced and subsonic loads.

http://https://archive.org/details/Complete_Guide_to_Handloading_Sharpe_1937/page/n387/mode/2up" rel="nofollow - http://https://archive.org/details/Complete_Guide_to_Handloading_Sharpe_1937/page/n387/mode/2up

Posted By: A square 10
Date Posted: December 19 2023 at 8:21pm

i think i might try this ive got the unique on hand and i can get the cast lead bullets from a friend

Posted By: martini1215
Date Posted: December 20 2023 at 3:57am

Many thanks for that.

The slugging of the bore is a useful thing to be able to do anyway and I shall download that information.

Regards Martini

Posted By: britrifles
Date Posted: December 20 2023 at 4:43am

Lyman reloading manual has cast loads for most calibers including .303. Lyman Cast Bullet Handbook is a good reference on the subject of casting bullets, reloading with cast bullets, etc.

For a 200 gr cast bullet, starting loads of 11.0 grains of Unique, 15.5 2400, 18.0 SR-4759, 20.0 IMR-4227, 21.0 5744 and 21.0 IMR-4198. This is out of the Lyman book.

You will need to put a slight flair on the case mouth, but not too deep, just enough to get the bullet base to enter the case neck. Also, the neck ID should be no more than .002 inches smaller than the bullet OD, otherwise seating the bullet will size it down.

.311 is a fairly tight groove diameter for the .303. Most barrels will have larger groove diameters, .313 - .316 (nominal groove depth is 0.005 inches on a nominal .3030 bore).

Accurate shooting depends largely on the bullet filling the full diameter right at the throat. To check this, take a pure lead cast bullet of approx .315 diameter and using a hardwood dowel, tap it into the bore from the breech end to a depth of about 3 to 4 inches from the breech end (mark the dowel at 3.5 inches). Then tap it back out from the muzzle end. Size your cast bullets to .001 over this diameter. Note that measuring the bullet OD is tricky with 5 groove rifling, you have to roll the bullet between your calipers.

Posted By: martini1215
Date Posted: December 20 2023 at 12:58pm

Thanks for the information gents, its going to be a learning curve but now I am retired I intend to keep my mind properly active.

All those years doing a job which pretty much was just a means to earn a living can now fund something I really do enjoy.