Subsonic rifle load data wanted for 303 Brit

[303Guy]

Can anyone help me determine a load for cast boolits in the 303 Brit that will be just subsonic? The powders I have are H4227/AR2205, Lil'Gun, Varget/AR2208 and H4350/AR2209.

Boolit weights are 230gr and 208gr.

I would prefer a load that nearly fills the case if possible.

The 303 Brit has a case capacity similar to the Krag and 308 (when measured to base of the neck - where the boolits will be seated to).

Thanks

[Ramsgate]

I don't have a 303 and I'm unfamiliar with half your in stock powders but heck, this is the internet and I'm not using my real name so here goes. First I wouldn't attempt to fill the case. You might be very happy with relatively fast powders that are not position sensitive and are content to have a massive amount of airspace. If you started with H4227 you might think about 10 grains to start. It would not be my choice. If you cozied up to some shotgun shooter and purloined some Red Dot (too easy, they don't have the giant brains of rifle shooters), you might start at about 8 grains. I shoot subsonic loads in .45-70 and .375 H&H most days and I use Bullseye, N330, N340 and SR4759. SR4756 should work well but here success has eluded me.

I would strongly guess that the 303 British would do very well with those bullet weights at subsonic velocities. And now that I've primed the pump the smart guys can chime in. Good luck.

[wiljen]

Subsonic in the 308 is usually best done with unique and trailboss - try one of those.

[303Guy]

Thanks. I can get 'Unique' in the form of a local manufacture - ADI and I think 'Trailboss' too (it might even me made by ADI). I'm just not sure the faster powders are ideal for heavier boolits. (We are talking very heavy for caliber).

Well, using what I have, I loaded up 10grs H4227/AR2205 behind a 230grainer and used a filler. Pressure was very mild so I tried 19grs behind a 262.5grainer and got the 'working pressure' I am looking for. (That means room for more pressure but high enough to register on the primer and burn clean). Next, I'll try 21grs behind a 230grainer. The 230grainer is the 262.5grainer with a massive hollow nose designed to open up at low velocity.


The middle one is the 230gr (the left one is 209gr). The R/H one is the 262.5gr FN.

230grHN/10gr 262.5grFN/19gr

However, I have no idea what velocity I am getting.

My reason to want to fill (or nearly fill) the case is to make double charging or overloading impossible. 19gr AR2205 is less than half the case volume and is getting close to full pressure loading so an accidental increase of double charge could be diastrous! Mind you, being at the wrong end of this boolit would be pretty damn dangerous too!

[35remington]

A full case and subsonic velocities with smokeless powder ain't gonna happen, even with Trailboss. At subsonic velocities, even the slow pistol/fast rifle powders start to get very low pressure and therefore unreliable and very dirty burning.

Fast shotgun powders seconded here. Start with around six grains Unique and go up or down as the chronograph and your chosen bullet weight allow.

On edit: after seeing the bullet weights you're using, 4227 should work after all.....but a caseful of appropriate smokeless powder with reliable pressures will be difficult to do at such low speeds.

[longbow]

303Guy:

I'll check my Lyman Cast Bullet Handbook for .303 Brit and .30-40 Krag. I know there are limited loads for both.

I have used up to 13 grs. Unique with pretty good results and as low as 10 grs. under a 314299 at 200 grs. and a homemade boolit of 215 grs. I think even the 10 grs. will be supersonic though. I have also used IMR4227 and IMR4198 with filler. Charges of around 20 grs. behind the 314299 do well but work up loads carefully because each gun is different and the filler adds another dimension too. I have not downloaded with IMR4227 and filler to get subsonic velocities though. Shouldn't be any danger in my view.

I am with you on the double charging thing and am leaning towards filler for that reason and others. So far I have had good success with filler though that is opening up a whole other can of worms.

I was reading JeffinNZ's .303 Pygmy posts thinking that a full size .303 with filler should produce pretty similar results ~ whisper like loads.

For low velocity loads and light charges Unique, Bullseye, Red Dot, 2400 and a few others should be suitable. For the most part they are not position sensitive and do not require filler but the small volumes do require careful charging and checking cases to avoid double charging.

I doubt I just told you anything you don't already know! Just an old man rambling.

Anyway, if I turn up any suitable low velocity loads I will post them for you.

Longbow

[303Guy]

... but a caseful of appropriate smokeless powder with reliable pressures will be difficult to do at such low speeds.

Mmmm. I had a feeling about that! The 230grHN/10gr H4227/AR2205 had lots of partially burned powder and velocity must have been real low. 19grs under the 262.5grainer burned real clean and could not have been too slow.

Ummm .... I don't have a chrono. I'm running blind here!

[303Guy]

I doubt I just told you anything you don't already know!

Actually, longbow, you have been most helpful! Thanks. Even at supersinc velocity, these fast powders will produce zero muzzle blast from a suppressor so the shot would still be like a sharp whip-crack. (Hey..., a friend has a suppressed 223 - it's like a 22LR HV suppressed. Very impressive!)

I would appreciate the Lyman data - thanks!

OK, so if I need faster pistol or shotgun powders to produce a 'whisper' then that's what I shall do.

Oh, the reason for going with such a heavy boolit is to make a sub-sonic boolit into a lethal close range feral pig/medium game gun (for rain and dense bush conditions). Soft boolits are showing promising results.

[sagacious]

... I'm just not sure the faster powders are ideal for heavier boolits. (We are talking very heavy for caliber).

Heavy-for-caliber bullets and a fast powder is almost unquestionably the most reliable and safe way to achieve the subsonic results you're after. I'm not loading the calibers you are, but in the 44mag, a very small amount of Bullseye behind a 400gr swaged lead slug gives me a very powerful and accurate subsonic rifle load. Works like a charm. The majority of recipes for the type of load you're attempting will involve fast powders. I load heavy subsonic loads in other calibers, and the fast-powder heavy-slug combo works reliably.

If you can get Unique, then you'de be competently advised to seek some out. Unique deserves it's name-- it is indeed unique. Safe recipes for Unique and lead slugs can be found for the 25ACP to the 460 Win mag.

My reason to want to fill (or nearly fill) the case is to make double charging or overloading impossible. 19gr AR2205 is less than half the case volume and is getting close to full pressure loading so an accidental increase of double charge could be diastrous!
...

There's no way around this. A partial-charge of slow powder can be just as disaterous as a double charge of fast powder. There in so sure solution, save for care in load assembly.

Also, you'll be using such small amounts of fast powder that a double charge may well do nothing more than give you only a little more velocity. My subsonic loads use truly tiny amounts of powder. In any case, these loads need to be loaded with care to function properly anyway, so one should take the time required to prevent mistakes. I weigh each powder charge on these subsonic rifle loads, as a small powder variation and a dirty bore can mean a stuck bullet.

Hope this helps, good luck!

[sagacious]

Since you have no chrono, and just as a point of reference, Lyman lists 10grs Unique and the Lyman 210gr 311284 as giving 1210fps, and that 13.5grs Unique gives 1450fps in the 303 British.

If you do get some Unique, and you wish to experiment, you might try down-loading from there.

Cheers, and be safe.

[longbow]

303Guy:

Here you go ~ all loads for .303 Brit using a Lyman 311284 @ 210 grs.:

- Red Dot; 10 grs.; 1245 FPS
- 700X; 9 grs.; 1165 FPS
- Green Dot; 9.5 grs.; 1190 FPS
- PB; 9.5 grs.; 1130 FPS
- Unique; 10 grs.; 1210 FPS
- SR7625; 10 grs.; 1170 FPS

Unfortunately, no pressures listed for .303 or .30-40 Krag.

As an indicator, Red Dot @ 10.5 grs. gives 1244 FPS and 27,000 CUP in a .30-06. >3o3 has a little less volume so pressure should be a little higher.

So, those loads are all supersonic but not by much. I bet a reduction of any by 1 to 2 grs. would make it subsonic.

Personally, I am leaning to IMR4227 and IMR4198 with filler but again, not subsonic, just nice light consistent loads and they are working well for me so far. I doubt either would work well in reduced load without filler though.

By the way, how does filler work with a suppressor? I would have figured bits of filler would get blasted into the suppressor requiring lots of cleaning.

Oh, and a warning if you are working your way down in charge... make sure the boolit leaves the barrel! Especially with a suppressor where you might not hear much.

A link you may enjoy:

http://www.guns.connect.fi/gow/arcane1.html

Okay, two links:

http://members.shaw.ca/cronhelm/SubsonicBullet.html

I hope that helps.

Longbow

[Ramsgate]

I weigh each powder charge on these subsonic rifle loads, as a small powder variation and a dirty bore can mean a stuck bullet.

I throw all charges. I use a Redding powder measure for the .375 H&H but use a Dillon 550B and load the .45-70 there in a progressive fashion as I shoot it a great deal. I always mop the bore after use and I always start with a wet bore. I do not do this with jacketed bullets but I do not anticipate ever loading anything but cast in these two excellent calibres. I spent some years fooling with puffs of this and that and frankly it was worse than a waste of time. No fillers no wads and usually no gas checks and both rifles never disappoint.

[303Guy]

Thanks, yes, very helful indeed! Interesting read, those two links. I was aware of the Valmet suppressor (ironically, I developed something similar 25 years ago for my mini-14! My current ones are a tad different in function but the same in size).

[303Guy]

Well, I just fired a 230grHN over 21.5grs H4227/AR2205 into a wet paper ball over dry sand with folded newsprint inbetween. The wet ball was fist sized. It captured fragments of the blown hollow nose and the hole in the folded print was substancial. The boolit penetrated the dry sand quite well and no doubt expanded further. Weight retension is 182gr. Once the sand is dry I shall sift it to see how much weight loss occured in the sand itself. (This is going to be one devastating small critter boolit!)

From the data gleamed I would say that 21.5grs H4227 would equal about 11gr Unique, velocity wise so probably subsonic or at least close to trans-sonic. Pressure would be about a medium full-house load so not much room for error.

Eddited to add;

Just checked the bore - clean as a whistle! (Apart from some dirt!)
I pushed a cotton wool ball through and what came out was seriously minimal
There is no sign of leading or anything like that.

So, My conclusion is that the load I used produced enough pressure to obturate the bore (like the boolit wasn't over-groove already) but muzzle pressure low enough not to upset the soft alloy boolit on exit.

Ready for field testing!

Thanks all for the very helpful suggestions and info. (Unique testing will be in a while to come - can't have transonic loads).

[dualsport]

It might be possible to reduce the case capacity some by using some experimental techniques I've read about. In one the guy inserted a piece of carefully cut paper into the case before loading powder. It more or less formed a tube against the walls of the inside of the case. Nitrating was tried to promote combustion of the paper. By reducing case volume you kill a couple birds with one stone.

[303Guy]

Now that you mention it, I have a whole bunch of cases with quite thick walls and hence reduced volume. The difference in volume is a little more than the volume of the neck. Quite a bit!

Lyman lists 10grs Unique and the Lyman 210gr 311284 as giving 1210fps, and that 13.5grs Unique gives 1450fps in the 303 British.

I'm wondering if I could extrapolate those numbers to get the 'expected' velocity with heavier boolits.

With H4227/AR2205 it would be a bit risky as at some point the powder starts to burn properly resulting in a rather dramatic rise in pressure and velocity but Unique should be quite predictable. I did play around with an equivalent many years ago in the 303 and for low pressure loads it really does work well. At that time I only had 180gr boolits (that did not fit the bore properly).

Mmmmm...... just thinking ..... H4227 at 21.5grs half fills the case. This makes it easy to see and check with a rod guage that the case is not overloaded.

[joeb33050]

Based on Mic Micpherson's table of case capacities the 303 British has about 96% the usable capacity of the 308 Win.
H4227 is going away because it is so close to IMR4227.
I have shot 200 grain bullets in 308 Win with IMR4227 down to 6 grains at ~544 fps, with round holes and reasonable accuracy.
Quickload estimates 308 Win 200 grain bullet IMR4227 velocities at:
16 gr. 1167 fps
15 gr. 1104 fps
14 gr. 1041 fps

It looks like charges in this region would give subsonic velocities in 303 British.
Take all the necessary precautions to keep from double charging, keep that flashlight handy.
joe b.

[303Guy]

Thanks for that.

So, it would seem that a 230grainer over 21.5grs AR2205 would be supersonic and that a 262.5grainer over 19grs would be subsonic - thereabouts.

I do know that a 225 grainer over 34.7grs Varget/AR2208 produces around 1800fps. Going through old load data I see I have loaded 30gr Varget/ under a 145gr boolit with cotton filler and 34.7gr H4350/AR2209 under a 200gr boolit. No hope of subsonic there I should think as has been said already! So, either I stay with AR2205 or go to Unique. Mmmm....

[canuck4570]

I shoot sub sonic to match my 22lr
I shoot my 30-06 at 1040 fps
I do it with 9.5 grain of Trail boss
the bullet is a Saeco r4 that weight 196 gr.....
with this load you should be close
I would go with 9gr to start and if you have a chrono just adjust yourself......
with this load the case shows no black mark and I shot all sumer long never cleaned the barrel and accuracy was great sub moa at 100 yards and 2 1/2 at 200 yards
shot around 3000 rounds.....

[redgum]

FYI:
http://castboolits.gunloads.com/showthread.php?t=71243