Thread: Slow Powder, Heavy GC boolit, anyone got a ballistics calculator?

Hi, looking for some help. Have not got a chrony but just want it to work safely.

Calibre .303 British, different no 1 Mk iiis and a No 4
All full length 24-25" barrels
204grain HP GC boolits from @shooternz
Federal 210 Large Rifle Primers
Case full to rear of bullet but not compressed, H414, 47grains charge is max it will hold that way.
Use: paper targets, deer, goats.

Reason for 414 is wanting to keep pressures low, both for safety and because shooting soft lead GC boolits and some of the barrels are more worn than others, hence going for a more gentle shove. Not too worried about pedestrian performance of H414 for reasons above, just definitely want to avoid going over 2000fps.

Anyone happy to put this in a ballistics calculator for a ballpark figure of muzzle velocity?

Assuming ~.313 seating depth and 100% fill...



Edit: 47gr...

Cheers @PommyMcPomFace!

Wow, the 47 grains is pooooshing that boolit out, but pressures skirting at the safety edge of 46,000 PSI, and likely stripping lead off. Still an impressive performance within or at the safety margin.

Staying well back seems better but "they" say H414 does not like too much empty cartridge space.

Would you be happy to also run the same parameters with 43 grains H414? (Should get me at/below 2000 fps, I hope).

If thats correct its way too fast for a cast bullet, thats close to the mk 7 jacketed speed and that weighs 174 gr! It probably is unsafe and will also boot like a bastard and lead like buggery.
Visit the cast boolits website for advice otherwise look up the adi web manual it has a section on trailboss and some other powders for cast.
I used to use 15 grains of imr 4227 in a p14 behind a cast 210 gr rn which did about 1400 fps, never couldd get cast bullets to work ok in a 2 groove no4 though.

Originally Posted by Marty Henry

If thats correct its way too fast for a cast bullet, thats close to the mk 7 jacketed speed and that weighs 174 gr! It probably is unsafe and will also boot like a bastard and lead like buggery.
Visit the cast boolits website for advice otherwise look up the adi web manual it has a section on trailboss and some other powders for cast.
I used to use 15 grains of imr 4227 in a p14 behind a cast 210 gr rn which did about 1400 fps, never could get cast bullets to work ok in a 2 groove no4 though.

Yes, will likely exit barrel lighter than when it entered. Not surprised at the figures though, cast lead bullets are much easier to push through the barrel than copper jacketed bullets.

Think I'm on to the right thing here --- what with the slower gentler push of a slow powder allowing a soft bullet to be pushed faster -- but lead bullets >2000fps are hard (pun intended).

My no 4 is a two groove too. )-:

I shoot a lot of cast bullets in 30, 9.3, and 45 cals and most of my loads use either pistol or fast rifle powders. Im not a great fan of trailboss but have used it a bit.
All the old books i accumulated when i got started nearly 40 years ago mention unique 10 grains as the starting point for just about everything, the theory being a short sharp boot in the arse gets the bullet to obturate properly and then just slide out. I still use the 10 gr load using blue dot for my 3030 308 and 9.3. No filler and std primers dont enlarge the flash hole whatever you do.
This is a page from a 1964 lyman manual i got in a 2nd hand shop covering the 303,, there are adi equivalents ffor just about all of these. SR 4759 was probably the best apart from the unique, the slower powders are likely to leave a lot of unburned grains in the bore which leads to inconsistent velocity.
As you will learn with cast bullets its not about speed and you will have a lot of fun experimenting.

you could always run the old tart on black smelly stuff............

47gr again, with case capacity reduced such that it represents a 100% fill...



43gr, same reduced case capacity...



14gr of Hodgdon Universal (ADI AP-70N)...

I don't recommend shooting these bullets faster than 1900fps most feed back I get is that 27.00gr 2206H is the load to start with
look for accuracy not velocity with cast bullets the HP will expand at under 1000fps the solid's will expand at 1400fps no need for
high velocity,
Experimenters have achieved over 3000fps with cast bullets with specialised barrels and very hard bullets that are totally useless for
hunting I can make the bullets but they will be the same price as jacketed ones so not worth the effort,
You are better off with stick powder if you go the slow powder route 4831 is popular with the slow burn rate cast bullet shooters in the States
fills the case and lowers the pressure you get some unburnt powder but it is easy to clean out just don't push the bullets to fast and cause lead fouling
that is hard to shift if left to build up.

Originally Posted by Micky Duck

you could always run the old tart on black smelly stuff............

Thanks @PommyMcPomFace and @shooternz.

He heh, could be tempted just to stuff it with BP and go. Saying that, BP pressure spikes are no joke. And I'd go for the sulfur free stuff.

As I indicated earlier, not looking for super performance, just to shoot them fairly fast/flat up to 2-300m max, while keeping chamber pressures as low as possible. Not just for safety, the SMLE action will handle it, but to minimise "shaving" of boolits when there is shallow rifling. If I load H414 for a target velocity of ~1800 fps I think that would would keep pressures well inside the comfort envelope of the cast lead boolit.

Like @shooternz said, a stick powder would be better as filling the case more. I did actually look for H4350 for this reason but GC only had equivalent H414 in stock. H414 is equivalent by weight but more dense as it's a ball powder, and I got it as it promised the ability to make some hotter but still lower pressure loads. But incomplete case filling can be required --- just like now when I'll probably have to go develop a load around 38grains of H414 which is about 75% of available space, and I may have to get some dacron wool or similar.

Anyway, as I now have H414 and TB, H414 is what I'm using for the supersonics. If H414 won't work accurately then it's back to the TB as the problem will be lack of bullet obturation. This web site suggests that for bullets of BHN 12 you need 17,000 PSI / 1180 BAR for proper obturation, but I think I really just need to get out there and try some loads. The obturation problem may be though why there is a tendency to use slow powders for heavy bullets - the heavier bullet has a bigger inertia and would that mean it obturates better than lighter bullets lower chamber pressures? Just a thought.

I like the software warnings about percentages of unburnt propellant at time of bullet exit. I guess an annoying big number with short barrels.

Originally Posted by Marty Henry

If thats correct its way too fast for a cast bullet, thats close to the mk 7 jacketed speed and that weighs 174 gr! It probably is unsafe and will also boot like a bastard and lead like buggery.
Visit the cast boolits website for advice otherwise look up the adi web manual it has a section on trailboss and some other powders for cast.
I used to use 15 grains of imr 4227 in a p14 behind a cast 210 gr rn which did about 1400 fps, never couldd get cast bullets to work ok in a 2 groove no4 though.

I had a look at the castboolits.gunloads.com web site as suggested and found a really helpful post:



30-06 and 200+ grain bullets (second last posting on the page).

Thread: 30-06 and 200+ grain bullets
Poster: Outpost75

"Safe rule is to use 75% of the jacketed charge for a bullet of the same weight, when using an extruded tubular powder similar to Varget, 4895, RL15, IMR4064.

Spheroidal powders such as H335, WC844/846, H414, W748, W760, H380, H450 etc. can't be reduced below 85% of free airspace or they get "hinky," so don't try it with those.

Slower extruded tubular powders such as 4350 and 4831 don't like it either!

With the "Garand" .30-'06 powders listed above you can reduce to 60% IF you use a loose Dacron fill tucked into the case mouth to take up some of the excess free airspace. NOT pushed down upon the powder!!!!

Larry Gibson has posted lots of good info on this.

I use 30 grains of the above powders with #311299 in the .30-'06 with Dacron fill for very good results.

In .303 British or .308 Win. the same 30 grains of the above powders will work fine without a filler."



So... I'll go ahead with 30 grains of H414, no filler, in .303 case with 204grain GC boolit seated 11.5mm, no prior neck sizing but crimped just above the driving bands to also tidy the mouth flare. See how that goes. I'll test at evening shoot on Thursday, will keep you posted.

24 done last night. Should be enough. Never enough.

Im looking forward to your results. I have been shooting cast in 303.s for nearly 50 years and have settled on fast pistol powder with 220 grain mixed alloy boolits at 1800ish fps. Best accuracy tho is if kept below the rpm threshold at 1650 fps. If you've looked up Larry Gibson on the cast boolit website he has several hours reading on rpm threshold and cast boolit alloy ,fit and lube.

Originally Posted by Driverman

Im looking forward to your results. I have been shooting cast in 303.s for nearly 50 years and have settled on fast pistol powder with 220 grain mixed alloy boolits at 1800ish fps. Best accuracy tho is if kept below the rpm threshold at 1650 fps. If you've looked up Larry Gibson on the cast boolit website he has several hours reading on rpm threshold and cast boolit alloy ,fit and lube.

LG has some posts there with very fast velocities, but hard bullets and target shooting. Someone there praised a go-to load with 35grains H414, similar boolit to mine, and 1970fps velocity. Don't know what the velocity will be for my current load, except it will be survivable by the boolit. Don't have a chronometer. Going to an evening shoot Thursday night at the Bruce Rifle Club, usually time for some messing about after the comp itself (in which I'll use my known-quantity HXP .303).

Draaaat! So at the range and will my boolit loaded babies allow me to close the bolt on them? Had to return to the car as the boolit got atuck in the throat and stayed there as I extracted the unfired case. It was neck sized and crimped and the boolits seated 11.5mm deep. Same rifle that case was fired in before.

Need to load an empty unprimed case and investigate further, not going to play with live rounds in my rifle in a residential area.

But it looks as if my H barrel SMLE is too tight chambered/throated for these boolits, not a worry as they were intended as
for my shot out de-lisle-to-be project . Will keep posting progress.