Question About Pressure?

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Matthew323

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Smokeless muzzleloaders are on my mind as a possible future build, as MtMonkey is urging me in this direction.

I have been spitballing a.....

1.) lightweight bolt action with a fluted bolt, possibly with integral Weaver/Picatinny scope bases as part of the reciever's bridge.

Thinking the AnTi X action from Defiance Machine.

2.) a Hankins/Arrowhead, large rifle primer, brass module capable, breech plug.

3.) a 16.25" long, cut rifled, 1:14" rate of twist, bull barreled, .45 caliber, 416 stainless steel barrel.

4.) a laminated, hard rock, sugar maple stock with lots of curl.

8 each, GrovTec, flush-mounted, 9/16"-18 threaded, sling swivel bases installed on both sides of the stock, as well as down the centerline on the underside of the forearm, and the belly of the buttstock.

Why so many sling swivel bases? So that any type of modern shooting sling may be utilized as an aid to holding the rifle steady, as well as carrying the rifle on one's shoulder when not in use. These would include, amongst others....

Ching sling
Rhodesian sling
CW sling
Galco RifleMann sling
Single-point tactical sling
2-point tactical sling
3-point tactical sling
Ultimate Firearms sling

All the above aside, my question has to do with pressure. A recent thread where a member was asking for chronograph data for a RL7 load for his rifle, and a response mentioning pressure testing equipment, got me to thinking (always a dangerous thing).

Where is the load data for smokeless muzzleloaders coming from?

Is it being extrapolated from existing data for cartridges?

Or, have private individuals invested in pressure measuring equipment so that they have the ability to safely develop smokeless powder loads for their own rifles?

Just out of curiosity, what's the minimum investment in order to get started with pressure testing loads with smokeless powders in muzzleloading rifles?

Thanks for your answers.

Edit: There doesn't seem to be much load data for smokeless muzzleloaders coming from the powder manufacturers themselves.

Can I speculate that the manufacturers see smokeless muzzleloaders as a threat to the already existing brass cartridge market?
 
Edge on Dougs (RIP) traced 100s of loads. Mostly with 209 primers. A guy on Hanks traced some too with LRMP. Setup correctly, Quick Load can be adjusted for a good guestimate. The thing is with software like that is all loads MUST BE 100% load density since we are always either 100% or compressed and that can make a massive difference in estimated peak pressures.

On a side note i cant imagine why you would want a 1-14 over a 1-18 or 1-20. There is ZERO need to spin them that fast. You wont be shooting 400gr+ dangerous game loads from a rifle like that. A Brux 45 1-18 will shoot any bullet you could possibly want to shoot sabotless. I would not go faster unless building a 40cal.
 
Oh and a company is now selling an action you may consider. You can easily have it lightened some. Its a SML specific action for about $850 iirc. All the bolt timing and stop for LRMP modules has already been done to it.
https://mesaprecisionarms.com/products/rifle-parts/muzzleloader-action/
As is a Brux 45cal #6 contour 26" long is 6lb 10oz using that action. That is with the brake and a Hankins pinned rail on it. Not sure how much lighter it would be with 8-10" less barrel on it.
https://hanksprecisiongunparts.com/...led-action-45-caliber-spml-6-barrel-contour-2
 
GM54-120,
The reasoning behind chosing a 1:14" rate of twist for a .45 caliber cut rifled barrel is to be able to stabilize the longest .40 caliber bullets in the .45 caliber-to.40 caliber, light blue Harvester sabots.

Such as the following bullets from Pittman.

ACCUMAX
225 grain × 1.270" long
228 grain Hard Core × 1.280" long
250 grain × 1.340" long


The above three bullets currently work with the light blue Harvester sabot. Their Sectional Densities & Ballistic Coefficients are as follows...

225gr × 0.199 SD × .340 G1 BC @ 2,800 fps
228gr × 0.202 SD × .359 G1 BC @ 2,619 fps
250gr × 0.221 SD × .385 G1 BC @ 2,800 fps


ACCUMAX
275 grain × 1.410" long
278 grain Hard Core × 1.425" long
300 grain × 1.480" long
303 grain Hard Core × 1.495" long

The above bullets currently must be shot as bore riding bullets in a .40 caliber rifle. With the advent of multiple .40 caliber muzzleoading rifles being brought to market, and the anticipated greater number of .40 caliber muzzleoading specific bullets that the mainstream bullet manufacturers will be offering for sale; it is hoped that Harvester will develop a new .45 caliber-to- 40 caliber sabot that will accommodate bullets measuring 1.5" long.

The Sectional Densities & Ballistic Coefficients for the above 4 bullets are as follows.....

275gr × 0.243 SD × .430 G1 BC @ 2,800 fps
278gr × 0.246 SD × .430 G1 BC @ 2,800 fps
300gr × 0.265 SD × .475 G1 BC @ 2,800 fps
303gr × 0.268 SD × .475 G1 BC @ 2,800 fps


That is why I would specify any .45 caliber barrel for a new rifle build intended for use with either BH209, or smokeless powders, to have a 1:14" twist.

It is a fact that a 1:16" twist, and a 1:18" twist barrel will stabilize the heaviest of the Pittman bullets listed above. However, Pittman recommends the use of a 1:14" twist for all 4 of the heavier bullets.

As far as shooting .45 caliber lead conicals in the 1:14" twist barrel, there is no real drawback to doing so. The Trapdoor Springfield .45/70 military rifle had a 1:16" twist, and that was for a Mil-Spec, 405 grain bullet. While I do not anticipate shooting BH209 substitute powder with 550 grain, .45 caliber lead conicals out of any smokeless rifle that I have built; it's nice to know that that capability exists with a 1:14" twist barrel.
 
Well, I answered my own question.

Bill Wiseman & Co. manufactures a Universal Reciever, and barrels, with which to conduct pressure testing. They also make fixtures that allow a person to place an actual functioning weapon in the fixture, and to measure pressure as the weapon is fired.

No prices listed on the website, so I am guessing that the test equipment is quite expensive.

https://www.wisemanballistics.com
 
You wont get a 275gr or larger 40cal to shoot worth a darn in current sabots. They wont handle it. WAY TOO SHORT and not made to handle bullets that large.

You say you want a 16" barrel but looking at super high BC bullets? Frankly that just dont make much sense to me. You wont ever get a bullet that heavy moving anywhere near 2800fps from a barrel that short? You will be lucky to get a 225gr moving close to that fast.
 
You wont get a 275gr or larger 40cal to shoot worth a darn in current sabots. They wont handle it. WAY TOO SHORT and not made to handle bullets that large.

You say you want a 16" barrel but looking at super high BC bullets? Frankly that just dont make much sense to me. You wont ever get a bullet that heavy moving anywhere near 2800fps from a barrel that short? You will be lucky to get a 225gr moving close to that fast.

If, and right now that's a BIG if, I was ever to build the rifle hypothesized in my earlier post, the reasoning behind the shorter barrel, is primarily to reduce the overall weight of the finished rifle. Any ballistic compromises that a short barrel brings to the table, I readily accept.

All of the data listed above for the Pittman bullets came directly from the Pittman website. While the numbers for the Ballistic Coefficients of the bullets is interesting, and thought provoking, it is the Sectional Density numbers that I am most interested in. A 16.5" long barrel will not be able to shoot ultra accurately out past about 500-600 meters. But, that's OK, because this is intended as a 300 meter, and closer, hunting rifle. Not a long range precision target rifle.

It is my intent to collect the data for a 16.5" long barrel using a both a chronograph, and a meteorological station. I am sure that in the final analysis, the muzzle velocities obtained using the various smokeless powders will show Ballistic Coefficients somewhat under the numbers published in the tables on the Pittman website.

And, I am perfectly OK with that, as it is the Sectional Densities that most interest me. The ability of any bullet to punch through bone, and maintain its weight is truly the performance I am looking for. Not whether the bullet is going to be able to carry its speed out to 1,000 meters with stability.

As long as I can push a .40 caliber bullet in a sabot out of the muzzle at a velocity that will allow the bullet to perform as the manufacturer intends, than however fast that bullet moves will be just fine with me.

At my current age of 67 years, any future muzzleloading rifle must weigh, all up with a scope, rings, sling swivels, and a shooting sling, less than 7.5 pounds. Characteristics that I consider essential in any new rifle are lightness, compactness, ambidextrousness, friendliness, handiness, and ergonomics.

It must be under 7.5 pounds.

It must measure less than 39" in length, and it must come to either shoulder cleanly, with the eye(s) immediately coming into alignment with the scope, and iron sights.

It must not have any attributes that in any way interfere with either carrying it, or shouldering it.

It must be esay to manuever into, and out of, vehicles, tree stands, and ground blinds.

It must be equipped with the best magnum recoil pad currently manufactured, and the length of pull must be no longer than 13.000", perhaps 12.500".

It must be capable of being utilized with the lightest of summer clothing, as well as the heaviest of winter clothing.

It must be equipped with multiple, flush-mounted, push button, sling swivel bases that will allow for any style of modern shooting sling to be used with the rifle. These sling swivel bases must be installed on both sides of the forearm out near the tip, both sides of the forearm 6" in front of the trigger, both sides of the butt stock 3" in front of the heel, in the center of the bottom of the pistol grip, on the centerline of the forearm behind the gunsmith adapter, & on the centerline of the belly of the butt stock 4" in front of the heel.

It must be equipped with two, flush-mounted, Spartan Precision Equipment, brass, Classic Gunsmith Adapters that will allow for the use of a bipod mounted under the tip of the forearm; as well as the use of any number of monopod, bipod, tripod, quad, or cent shooting systems mounted at the balance point of the rifle.

Make NO mistake about this, I intend to hunt for as long that GOD will allow me to do so. Hopefully, that will be into my 80's. As a reasoning man, my intelligence, and my gut, tells me that trying to carry a 8-12 pound rifle around at 80 something years old is not a smart thing to do.

That's why I am not going to have built a traditional longrifle with a .58 caliber, or larger bore. With barrels that must measure at least 38" long in order to be considered a longrifle, there is no way to get the weight of a .58 caliber, to .66 caliber, curly maple stocked longrifle under 8 Pounds. And, that weight would not take into consideration sling swivels, a sling, and GOD forbid; a scope base, rings, and scope.

That's the other gremlin hiding in the closet, my eyesight. In a word, it sucks. To be able to ethically hunt at any distance over 20 meters, I must use a telescopic sight.

The best of these scopes are going to cost a pretty penny in order to get the superb light gathering ability that my eyesight demands. Ordinary scopes that would be a good fit for someone with better eyesight than I have simply lack the clarity that I need. This means a hefty pricetag for Austrian, German, or Japanese optics.

Right now, that would be a Swarovski, Z6i, 2-12 × 50mm riflescope with an 4A-I illuminated reticle, weighing in at 19 ounces. After a lot of time spent online, and a lot more soul searching, this is the best compromise that I can currently see as regards to light gathering versus total weight of the scope.
 
Fury 401 240gr WILL shoot and its claimed BC is something like .360. A Simple rifle like a CVA Scout can get that moving around 2500fps, maybe a tad more. That is with current sabots and commonly used powders. I may have another barrel put on my NULA. Current weight is 7.65lbs with a Razor HD LH 2-10x40. I will drop back to a 24" barrel from a 26" but keep as close to the same contour as i have now. Should be super close to the same weight.

A possible way to get what you seek is with a Howa Mini Action and around a 20" barrel.
My review rifle came fitted with a black stock with a 13.8 inch length of pull and a very soft rubber recoil pad. Overall length is 39.5 inches and with the included scope mounted the rifle weighed in at just 7.4 pounds.
 
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If, and right now that's a BIG if, I was ever to build the rifle hypothesized in my earlier post, the reasoning behind the shorter barrel, is primarily to reduce the overall weight of the finished rifle. Any ballistic compromises that a short barrel brings to the table, I readily accept.

All of the data listed above for the Pittman bullets came directly from the Pittman website. While the numbers for the Ballistic Coefficients of the bullets is interesting, and thought provoking, it is the Sectional Density numbers that I am most interested in. A 16.5" long barrel will not be able to shoot ultra accurately out past about 500-600 meters. But, that's OK, because this is intended as a 300 meter, and closer, hunting rifle. Not a long range precision target rifle.

It is my intent to collect the data for a 16.5" long barrel using a both a chronograph, and a meteorological station. I am sure that in the final analysis, the muzzle velocities obtained using the various smokeless powders will show Ballistic Coefficients somewhat under the numbers published in the tables on the Pittman website.

And, I am perfectly OK with that, as it is the Sectional Densities that most interest me. The ability of any bullet to punch through bone, and maintain its weight is truly the performance I am looking for. Not whether the bullet is going to be able to carry its speed out to 1,000 meters with stability.

As long as I can push a .40 caliber bullet in a sabot out of the muzzle at a velocity that will allow the bullet to perform as the manufacturer intends, than however fast that bullet moves will be just fine with me.

At my current age of 67 years, any future muzzleloading rifle must weigh, all up with a scope, rings, sling swivels, and a shooting sling, less than 7.5 pounds. Characteristics that I consider essential in any new rifle are lightness, compactness, ambidextrousness, friendliness, handiness, and ergonomics.

It must be under 7.5 pounds.

It must measure less than 39" in length, and it must come to either shoulder cleanly, with the eye(s) immediately coming into alignment with the scope, and iron sights.

It must not have any attributes that in any way interfere with either carrying it, or shouldering it.

It must be esay to manuever into, and out of, vehicles, tree stands, and ground blinds.

It must be equipped with the best magnum recoil pad currently manufactured, and the length of pull must be no longer than 13.000", perhaps 12.500".

It must be capable of being utilized with the lightest of summer clothing, as well as the heaviest of winter clothing.

It must be equipped with multiple, flush-mounted, push button, sling swivel bases that will allow for any style of modern shooting sling to be used with the rifle. These sling swivel bases must be installed on both sides of the forearm out near the tip, both sides of the forearm 6" in front of the trigger, both sides of the butt stock 3" in front of the heel, in the center of the bottom of the pistol grip, on the centerline of the forearm behind the gunsmith adapter, & on the centerline of the belly of the butt stock 4" in front of the heel.

It must be equipped with two, flush-mounted, Spartan Precision Equipment, brass, Classic Gunsmith Adapters that will allow for the use of a bipod mounted under the tip of the forearm; as well as the use of any number of monopod, bipod, tripod, quad, or cent shooting systems mounted at the balance point of the rifle.

Make NO mistake about this, I intend to hunt for as long that GOD will allow me to do so. Hopefully, that will be into my 80's. As a reasoning man, my intelligence, and my gut, tells me that trying to carry a 8-12 pound rifle around at 80 something years old is not a smart thing to do.

That's why I am not going to have built a traditional longrifle with a .58 caliber, or larger bore. With barrels that must measure at least 38" long in order to be considered a longrifle, there is no way to get the weight of a .58 caliber, to .66 caliber, curly maple stocked longrifle under 8 Pounds. And, that weight would not take into consideration sling swivels, a sling, and GOD forbid; a scope base, rings, and scope.

That's the other gremlin hiding in the closet, my eyesight. In a word, it sucks. To be able to ethically hunt at any distance over 20 meters, I must use a telescopic sight.

The best of these scopes are going to cost a pretty penny in order to get the superb light gathering ability that my eyesight demands. Ordinary scopes that would be a good fit for someone with better eyesight than I have simply lack the clarity that I need. This means a hefty pricetag for Austrian, German, or Japanese optics.

Right now, that would be a Swarovski, Z6i, 2-12 × 50mm riflescope with an 4A-I illuminated reticle, weighing in at 19 ounces. After a lot of time spent online, and a lot more soul searching, this is the best compromise that I can currently see as regards to light gathering versus total weight of the scope.
I’m your age and like you also intend to deer hunt as long as I live, God willing. I like the way you think regarding going lighter but using the higher quality optics and materials to lighten your custom built muzzleloader. I’m following this thread and hope to learn more as your plans develop. Stay strong my brother. Isaiah 40:31
 
Hey my friend ,Bruce isn't on here anymore, I hope he comes back one day ,I miss him on here ,I'll tell him that you commented on his thread here ,I still talk to him on the phone on a regular basis,try to keep him in the loop ,I have a project that if I get it completed I'm going to try to include one of his out of the box ideas.
 
And what happened to JeffB1961 I believe he went by. I was following along his Woodman muzzy order but haven’t seen anything from him for a while? I‘m kinda on the fence with the woodman but keep telling myself I don’t really NEED one.
 

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