Smokeless barrels and prefits

[Farmerboy78]

Guys, so ive gotten into a hankins prefit .45 cal recently and I am new to sml. I've been reading here and other places about safe loads... heavier built rifles can take larger loads than prefits/breakactions. But my question is this, how are loads deemed safe? How are the barrels tested to show they can handle x amount of pressure?

 

[michiganmuzzy]

Great question. I wonder the same thing. Im on my first prefit sml barrel job too

 

[03mossy]

This is all way above my pay grade but they use pressure tracing equipment. It’s somehow tests the amount of force on the barrel.

 

[michiganmuzzy]

This is all way above my pay grade but they use pressure tracing equipment. It’s somehow tests the amount of force on the barrel.

Do they up the psi till barrels fail? Then call half that, (or some other percentage) a safe max pressure?

 

[quaid]

From the reading I've done, many barrel makers test rarely, if at all. They certainly don't test every barrel.

My hope is that someone tested barrels with various dimensions and made from various materials, and all others are at least following the leader (mimicry).



I don't know what PSI my barrel is 'rated for' aside from the builder saying that the savage 10ML and 10ML-ii recipes are safe. Did he test that? Unlikely... but I can approximate the peak pressures of those loads in the 10ML and use them as a pressure benchmark.

From there, I can use QuickLoad and/or Gordon's Reloading Tool to estimate pressures for various loads. This is something I'm trying to learn right now. Specifically I'm exploring GRT right now (free is appealing?).

With estimated loads derived, I can back them down a bit and shoot them...observing pressure as I slowly increase the charge weight. Right now I can only observe pressure by looking at the primers in the AGS gen 2 modules, or the powder-facing cup of sabots I recover. This method is imprecise at best, and dangerous at worst. A better way would be to measure the pressure with something like PressureTrace II.

In the absence of officially published load data, many people seem to be making educated guesses. That makes me uncomfortable, and it's the reasons I haven't tried a load of 3031 with a 385gr full bore lead bullet yet...I'm not confident in the load data.

 

[michiganmuzzy]

From the reading I've done, many barrel makers test rarely, if at all. They certainly don't test every barrel.

My hope is that someone tested barrels with various dimensions and made from various materials, and all others are at least following the leader (mimicry).



I don't know what PSI my barrel is 'rated for' aside from the builder saying that the savage 10ML and 10ML-ii recipes are safe. Did he test that? Unlikely... but I can approximate the peak pressures of those loads in the 10ML and use them as a pressure benchmark.

From there, I can use QuickLoad and/or Gordon's Reloading Tool to estimate pressures for various loads. This is something I'm trying to learn right now. Specifically I'm exploring GRT right now (free is appealing?).

With estimated loads derived, I can back them down a bit and shoot them...observing pressure as I slowly increase the charge weight. Right now I can only observe pressure by looking at the primers in the AGS gen 2 modules, or the powder-facing cup of sabots I recover. This method is imprecise at best, and dangerous at worst. A better way would be to measure the pressure with something like PressureTrace II.

In the absence of officially published load data, many people seem to be making educated guesses. That makes me uncomfortable, and it's the reasons I haven't tried a load of 3031 with a 385gr full bore lead bullet yet...I'm not confident in the load data.

here are a LOT of pressure traces, figuring out how to find what your looking for is really the tricky bit.
https://app.box.com/s/7u86evwrvgn3wmxpdzndtnzjcr04dfv2

 

[Farmerboy78]

Exactly, so do the traces test how much flex the barrel maker has under load? Just curious why a small shank is good for x amount of pressure. I really would like to understand to know more about what's going on with it. Instead of going by the seat of my pants...

 

[BuckDoeHunter]

What load info. did Hankins give you? What powder and bullet do you want to shoot? There is a lot of good load info. on the net but you also have to be careful and do your research. 60 grains of H or IMR4198 and a 275 grain bullet are a good starting point. Hankins was going to pressure test a barrel with increasing charges until it burst but I don't think he ever did it. ArrowHead Sporting Goods did a pressure test on his breech plug a while back and has it on video, I can't remember the charge amount but it was up there.

 

[peteo]

Here is a question answered by Randy Wakeman years ago. I in no way recommend a savage barrel be loaded greater than 35,000 PSI as a max load. This was a controlled test for safety standards only. Stay safe.
Q. Is the Savage 10ML-II safe?

A. Not only is it "safe," it is the safest, strongest muzzleloader ever made. Its very design was inspired by the failure of a conventional muzzleloader that resulted in injury. Smokeless powder is the safest blackpowder substitute yet devised. It is less flammable, more impact resistant, and safer to handle and store. The Savage 10ML-II has been tested to 129,000 PSI-no other muzzleloader can make that claim. That is well over 250% of any recommended load. The Savage 10ML-II is the only muzzleloader made that can pass SAMMI centerfire standards.

 

[Farmerboy78]

Hankins said 65gr 4198 with a 275... I have accuracy at 66gr... but I am just curious how high is physically the ceiling of safety with my setup. Just curious if I could squeeze out a little more speed AND be safe

 

[peteo]

Barrel diameter at breech and length before taper matter in the pressure capability along with shank, barrel nut or no barrel nut and receiver style along with caliber all matter. The 65 grain load of IMR4198 and a 275 is what Jeff recommends on his CVA hinge gun conversion. There are so many variations that need to be considered before a safe limit can be stated. I would ask the supplier of the barrel.

 

[HV-Muzzleloaders]

You might want to purchase the computer program QuickLoad, which helps predict pressure with various components.

I would start by trying the Harvester High Pressure sabots P/N 4540B with some 200 grain Hornady 40 caliber bullets, using 85 grains of H4895. The predicted pressure by QuickLoad is under 30,000 psi and the velocity is around 2700 fps.

I initially shot 92 grains but backed off down to 85 grains.

The shank diameter on the blued rifle is 1.125" The Savage rifle is 1.200".

Since this video was made, I removed the brake from the blued rifle and put a soft slip-on recoil pad on it instead. Yesterday I shot a 3 1/2" group with it at 300 yards. (3 shots)

High Velocity Sabot Loads:

 

[MeatMachine]

Peteo, If anyone believes that I have a bridge to china to sell them. A small or even a large shank nut barrel with a half inch hole through it and surviving 129000psi is highly unlikely. A cva switch barrel apex has a larger shank than the 10ml2 and its a higher quality stainless steel.

 

[Farmerboy78]

Quickload would be great, if I knew what the barrel is rated for

 

[D55]

Quickload would be great, if I knew what the barrel is rated for

Sent you a PM

 

[peteo]

Peteo, If anyone believes that I have a bridge to china to sell them. A small or even a large shank nut barrel with a half inch hole through it and surviving 129000psi is highly unlikely. A cva switch barrel apex has a larger shank than the 10ml2 and its a higher quality stainless steel.

I would agree but that is what was stated. I know I bulged my small shank 50 barrel with 66grains of IMR4198 shooting a 458 JHP rem and an orange mmp sabot behind a stock savage ramrod with a brass bullet seater screwed in. It was a vicious recoil and the barrel stayed together but bulged for about 4 inches. I still thank God for the quality of Savage barrels. I have no idea what the pressure was but I have always wondered.