Cast load data 7.5x55mm

[Tommygunn]

I'm hoping somebody here can help

I want to shoot cast from my new toy (1911 schmidt rubin) and I will be projecting a 150gr bullet with XMP5744, as it's what I have to hand.

A brief web search, and a little experience from loading other calibres, suggests around 22gr of 5744 is the ticket, but wondered if anybody has the actual min/max numbers to hand?

[dromia]

What velocities are you looking for?

Have you checked the boolit for fit?

[Tommygunn]

Good question, CB's are gas checked but certainly below 1800fps I'd think - to shoot over 100yd range

.309 bullet looks to be about right, though I confess it's new enough to me that I haven't got around to slugging the old girl to be absolutely certain.

I just haven't got load data for 7.5 Swiss in my Lyman manual, (49th ed.), really ought to get the Lyman cast bullet manual I suppose, though I don't know if it's in there either! I load for a few others inc. .303, 7.62 Russian etc. which I have data for, and work quite well with 22-24gr of 5744 so presume the recipe ought to be transferable?

[dromia]

The beauty of the 1911s over the K31s is that the 1911s have freebore so it is easier to get boolits to fit. Ideally the boolits should fit the freebore "throat" if possible. if that is too large for the cartridge to chamber then get boolits 1-2thou over groove diameter.

It is usually better to go for a heavier for the calibre boolit when using cast due to its lower start pressure and help with consistent powder burn.

I'm travelling today and tomorrow so away from my data but will post tomorrow or Sunday with my 5744 experiences unless someone chimes in first.

1200-1400 fps is fine for 100 yrds.

You'll probably get away without gas checks, make sure it is a soft alloy boolit not hard, hard boolits cause leading, tumble lubing in 45-45-10 will suffice for lube and you should even get away without sizing.

For 100 yrd shooting I usually use 5-7 gns of a fast pistol powder like N320 but there is nothing wrong with 5744 which burning rate I use for loads around the 1600-1800fps range.

[Tommygunn]

I'd heard that, it rather helped with my choice of rifle, though I always go for the older rifle if there's a choice!

I always size and gas check to be sure. Look forward to hearing your further recommendations, thanks!

As an aside I had thought about getting hold of some red dot and trying out "the load" which I've heard lots of good things about, plus at 13gr a pop a tub of powder should last longer...

[dromia]

Harris superseded the Red Dot load with 16 grains of 2400, see sticky at the top of this forum.

13 gns of Red Dot is a bit stiff for fast burning powders, also I suspect that Red Dot's burning rate has got faster over the years.

It used to come after Bullseye in the charts but now it come before it.

Harris's article says it all really and is the seminal work on cast boolits in military rifles, I have shot 10s of thousands of the loads in nearly every military bolt action calibre rifle there is over the years and his recommendations just work, so long as you get the boolit right for the rifle.

[Tommygunn]

I see a tub of Alliant 2400 in my future...

If it's possible to say, how much variation would be 'safe' for experimentation - 1-2gr either way, or is 16gr the magic number for my various old ladies (7.5x55 to 8x56r)?

[dodgyrog]

Harris superseded the Red Dot load with 16 grains of 2400, see sticky at the top of this forum.

13 gns of Red Dot is a bit stiff for fast burning powders, also I suspect that Red Dot's burning rate has got faster over the years.

It used to come after Bullseye in the charts but now it come before it.

Harris's article says it all really and is the seminal work on cast boolits in military rifles, I have shot 10s of thousands of the loads in nearly every military bolt action calibre rifle there is over the years and his recommendations just work, so long as you get the boolit right for the rifle.

I'm surprised he went from fastest to slowest pistol powder in one jump. I would have thought Green Dot or Herco would have done the job, even Blue Dot which I personally like.

[dromia]

I don't know where it says that is what he did, what I know of Ed and his work I suspect that he would have tried every powder he could lay his hands on. In his writings he is reporting what worked best.

Also as serious cast boolit aficionados know you want a slower powder as the desired velocity increases to ensure boolit support before peak pressure.

2400 isn't a magical powder but its burning rate is right for cast boolits at 1600-1800 fps in the 30 calibre case capacity range. 5744 is a very popular powder with CBA shooters and it is a bit slower than 2400, I usually use N110 or N120 as my go to powders for this type of loading along with Ramshot Enforcer. I use these powders because they work and very importantly are readily available here in the UK.

With 5744 20 gns would be a good starting point giving around 1600-1700 fps, work up from there to say 24 gns. This isn't a maximum load but most likely your boolit will be failing by then.

For 100 yrd shooting I'd keep it simple with no gas check, tumble lubed (45-45-10), unsized boolits and fast pistol powders in the 7-11 gn range. I am finding Ramshot Zip to be a particularly good powder for this type of loading.

You can experiment either side of 16 gns of 2400 but the best accuracy (i.e velocity) comes around that. You could safely increase the charge of 2400 but your boolit would likely fail long before you reached a near maximum safe load.

Accuracy in cast boolit shooting rarely if ever comes with maximum loads.

My 1000 yrd cast loads with 200+ gn boolits travelling at 2200-2400 fps are all loaded at less than maximum.

With 5744 expect unburnt powder but don't worry about it.

[Tommygunn]

Righto, I'll work with what I have for now (5744) which has worked ok for me thus far and try some 2400 when I next get the chance

Thanks again