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View Full Version : OK this is going to sound a little weird, PP steel .50 BMG bullet



earthquake
06-18-2021, 02:55 PM
I would like to try to shoot a paper patched steel bullet in a .50 BMG rifle for 1000 yds competition. I am a member of the FCSA [Fifty Caliber Shooters Assn.] Years ago they used to shoot dead soft steel bullets and some guys had pretty good luck with them but you only got about 1000-1500 rounds before the barrel was gone.
I would like to design a Bore rider style bullet that has a 1" long paper patch, do you think it would work with the pressure a fifty generates? I was thinking a .500" diameter bullet with a shallow groove in the middle for the PP, what kind of paper would work best? the PP would be wrapped to around .512"-.515" for a tight fit in a .510" bore.
I am also concerned about the muzzle brake, If you were shooting it through a "Heavy Gun" class rifle [50lbs max] you could shoot it with out a brake because the recoil would not be too bad with a light weight steel bullet [about 600-700 gns], I would like to get the velocity up to about 3200 FPS to get the travel time down to about 1 second to the target. right now I am getting about 2700 FPS with 750gn A-Max's.
As you can tell I don't know much about PP bullets just wondering if it would work.

eQ

R-71
06-18-2021, 04:39 PM
A Bore diameter lead PP bullet will slug up to fit the bore. Smokeless powder “may”work especially With the charges that a 50 BMG would use. What would you gain to wear your barrel so quickly? You should probably have this topic moved to the smokeless PP section.

Skipper
06-18-2021, 05:04 PM
Why not bronze or brass?
Might be easier on the bore.

country gent
06-18-2021, 05:31 PM
A steel slug probably wont swell to seal the bore much being much harder than lead, even when anealed to dead soft. The plus is lathe turned as quick program change and profile shape size bearing length can be changed.

Bonze brass or copper might be a better choice,

Also Paper is abrasive so wear with the had steel bullet nay be about the same.

What would a sabot with say a 40 cal bullet in your stated weight range do?

earthquake
06-18-2021, 06:32 PM
I did not see the smokeless powder PP bullet sub forum, sorry about that.
Mods if you please move this I would apricate it

thank you

Nobade
06-18-2021, 08:27 PM
Bore wear and poor accuracy aside, steel bullets would have a terrible ballistic coefficient and sectional density, they're just too light. Tungsten in sabots like the SLAP rounds, or lathe turned leaded bronze solids would be the way to go if you don't want cup and core bullets.

MUSTANG
06-20-2021, 03:30 PM
Not sure I agree with Nobade; although for traditional approaches he has good points. The picture in the following link is a cutaway drawing of an M2 50BMG with the case/powder/ball depicted.

https://cartridgecollectors.org/cmo/cmo06may.jpg

In the picture one can see the sectioned M2 Ball with the Steel Penetrator exposed. Seems that a soft steel "boolit" could be paper patched and fired as we do with lead. In the M2 projectile in the picture; the Copper alloy outer jacket provides the same function as the Paper Patch would. Yes, lead is far more dense than steel, brass, Bronze, copper, etc..., and the engraving of rifling/grip on the projectile core is different in each metal, but if the objective is to develop a projectile and paper patch it, then theoretically all would work - the internal and external ballistics for each would be different.

Harter66
06-20-2021, 05:30 PM
Based on reading from very old test sheets the 50 BMG is exactly what it is often described as , a 30-06' scaled up to 50 cal . A 750g linked ball runs 2700 fps on 55 kpsi from a 34" barrel . Again old test sheets circa 1953-74 lots . I know zip about actually shooting or loading them and I left that employ 3+ yr ago .
Presuming an alloy similar to steel jackets low carbon and copper added , just thinking here Im tip toeing around the drop off where I get over my head quick , I think about .0005 over land dia might be the place to start .

Paper . Go back up to the BP paper patch area and read the paper selection guide in either 2-3 goes or read it twice on different days . It's well written . There is a mountain of information in it and unless one has an identic memory capable line item search and recovery it's just too much to manage in a single read . Someplace between money paper , very expensive high cotton calligraphy paper and and chain matrix printer paper lays the one you're going to want . Then there's weight and density ......

Patch lube ........ IDK jack diddley but I've done some small cal high pressure work . Shoot the first 10 dry . I use a modified Darrs lube on naked cast and once the barrel settles down a little bit I finger a little bit on the front/top half of the patch .... But I think you're going to be better served by something more like dry graphite painted on the finished wrap before loading .

A no tail wrap isn't as easy to do but I think it will offer better internal performance and sealing than a twisted or folded tail . See blowing up ones skirt .

Most of the above has been tested to some degree by me with lead alloys up to whoops there's no primer in that case , what do know a Carcano will take 70 k . Down to 1800 fps in an SKS with a 200 gr cast spitzer . In 26,27,28&30/31 cal .

Others here have done a lot more work and reached past 3000 fps in a 300 RUM with sub MOA .

Steel bullets are another chapter in a different book . The best you can do here is take the the information from BP and plot the major changes to smokeless then the major changes from 1-20 to lino and if it's still here the major changes to jacketed and brass solids . That should give you a loose guide to what needs to change to get a steel bullet out of the barrel and on to a barn door at 100 yd .

414gates
11-05-2021, 08:51 AM
Where do you get steel bullets from ?

MUSTANG
11-05-2021, 11:08 AM
Where do you get steel bullets from ?

Make them yourself on a lathe. As an example from Home Depot:

1/2 in. x 48 in. Plain Steel Round Rod - $11.98

And from Amazon:

1/2 in x 8 in Copper rod (2) - $25.99


As one can see; a machined steel bullet for paper patching would be cheaper than a machined copper bullet for paper patching (of course a true 50BMG bulet goes at about .510 diameter).

One could also look at a cast 50BMG Bullet such as a mold from NOE:

https://noebulletmolds.com/site/513-875-lfn-bmg/
291269

Or an all ready cast and Powder Coated bullet such as:

https://www.robsbullets.com/store/p35/.510_890gr_LFN-GC_hardcast_powder_coated_bullet_for_50BMG.html#/

rockrat
11-11-2021, 11:29 AM
I would think that you will definitely need to take the muzzle brake off. I don't think the soft steel bullets were made of 1018 cold rolled that you would find at the hardware store. Now, I have often wondered about a groove dia. steel bullet, paper patched and a driving band on the base of the bullet, like artillery rounds