Knurled Jacketed Bullets For Double Rifles

[mgstucson]

Since double rifles are sometimes older, and rated for less pressure, I have made a knurled jacketed bullet that can be dry lubed like lead bullets, and have less friction going down the bore since there is less surface area of the bullet touching the barrel when fired. What do you think of this concept.

This is a 375 bullet using cartridge brass as a jacket. This was made for my 375 Flanged double rifle.

 

[SRvet]

Aren’t calibre sized drive bands and a smaller central shank not a better way to go rather than just using lubrication?

 

[michael458]

 

[mgstucson]

@srivet,
Yes, driving bands are absolutely a better arrangement and absolutely crucial to be able to make monometal bullets work at all because of increased pressure from shooting long for weight monometal bullets. Knurling is a way to decrease barrel friction using lead core bullets. Driving bands are still a great idea for lead core bullets and could be created on lead core bullets with a series of cannelures on the bearing surface of the bullet. I need to make enough of theses to do firing tests to know if the juice is worth the squeeze. Thanks for the great feedback.

@michael458,
Flatnose monometals are great in a few circumstances where solids are needed, but many if not most dangerous game circumstances call for the much greater crush cavity and quicker incapacitation attained by expanding bullets. That is why most PH's recommend them. monometal solids certainly have their place though.

 

[Hornedfrogbbq]

@srivet,
Yes, driving bands are absolutely a better arrangement and absolutely crucial to be able to make monometal bullets work at all because of increased pressure from shooting long for weight monometal bullets. Knurling is a way to decrease barrel friction using lead core bullets. Driving bands are still a great idea for lead core bullets and could be created on lead core bullets with a series of cannelures on the bearing surface of the bullet. I need to make enough of theses to do firing tests to know if the juice is worth the squeeze. Thanks for the great feedback.

@michael458,
Flatnose monometals are great in a few circumstances where solids are needed, but many if not most dangerous game circumstances call for the much greater crush cavity and quicker incapacitation attained by expanding bullets. That is why most PH's recommend them. monometal solids certainly have their place though.

What is your goal on this? What problem are you trying to solve or are you just thinking this would be an improvement in velocity without adding pressure or?

 

[mgstucson]

What is your goal on this? What problem are you trying to solve or are you just thinking this would be an improvement in velocity without adding pressure or?

Yep. That is it. To see if there is a easy way to modify bullets so that people can shoot the same velocity at less pressure, or acheve higher velocities at the same load and pressure. My doubles are all modern steel rated to shoot high pressure cartridges like the 30-06. but others have older guns that may need to reduce pressure as much as possible. It doesn't seem there are a lot of people trying to focus on technological advancements to address the issuses that double rifle shooters face. If people who are shooting loads at the top end of the velocity and pressure curve for their gun, to get it to regulate, this mod to the bullet may help them shoot the same velocity at less pressure, and therefore be gentler on older guns. I haven't experemented to see if this effects the terminal performance of the bullet either. It is just an idea I am tossing around to see what the learned people here think of it. It may not be helpful at all, but you never know.

 

[Hornedfrogbbq]

 

[michael458]

Flatnose monometals are great in a few circumstances where solids are needed, but many if not most dangerous game circumstances call for the much greater crush cavity and quicker incapacitation attained by expanding bullets.

I take it you are not familiar with the Raptor........... In the first days it was called Non-Con, for Non-Conventional ............ Today, Raptor. The single most devastating, tissue destroying, trauma inflicting bullet that ever went to the field. Available in all calibers from .224 to .620 caliber.

And beyond that, Barrel Strain tests were done in various calibers in double rifles, barrel strain measures how much a barrel expands as the bullet passes that point, the CEB Solids and Raptors, along with the North Fork micro bands consistently gave less barrel strain than any other bullets tested. Benchmark bullet was a Woodleigh Soft, considered safe in Double rifles, anything less than the Woodleigh soft strain was considered safe as well. Strains above the Woodleigh Soft were considered questionable.

 

[michael458]

It doesn't seem there are a lot of people trying to focus on technological advancements to address the issuses that double rifle shooters face.

We did all that work here going back to 2010. The Cutting Edge Bands were designed to be safe in double rifles. We also tested the North Fork Micro bands and they were hand in hand with the CEB both in brass and copper. We tested a large variety of different bands, number of bands, different diameters within caliber to see what worked, and what did not work. Finally settling on the 4 bands you see pictured above.

The first barrel strain tests were conducted in 2010 with a 470 NE Double Rifle.

We went with a strain gage 4 inches back from the muzzle, our mistake was still using full pressure loads, which lead to higher numbers at the strain gage in the front. All calibers/cartridges tested from that point on was with reduced loads, and chamber pressures never reached the strain gage in the front. At that point it only measured the amount the barrel expanded, 4 inches back from the muzzle, with no chamber pressure layover.

We moved on to 500 NE and I also did extensive test work in .458 caliber using a bolt gun I had set up. The bullet does not know what the barrel is, or cares.

Some samples of what Barrel Strain looks like on a pressure curve;

That is just some samples of some of the test work done here. From this work we determined the best overall band design for the Cutting Edge Bullets, and that is what you see today. I experimented some with the North Forks, but really only equaled and not surpassed, but I like my band design a bit better regardless.

Barrel strain is effected by Diameter and Bearing surface....... This is why some of the Barnes and the Woodleigh both are found less than caliber in many cases. North Fork and most all CEB are full caliber. In the beginning we thought we would do a .458 caliber 480 gr bullet for the NE guns, reduced it to .457 caliber. It remains that to this day. Good bullet for sure, but later we went to all the rest being full caliber. It really did not make much of a difference in that band design.

We also worked with 2 band designs, which was ok, but very limited and difficult to load and crimp properly, but you can see a massive difference in bearing surface.

My Test Partner is a Double Rifle fanatic, having well over 2 dozen or more. He is the main reason we did the test work in double rifles, he wanted a "Better Mousetrap" and he got it. In 500 NE he saw what incredible success I was having with my .500 caliber cartridges, and reduced weights. He came up with this combination for his 500 NE rifles, a 510 #13 Solid and 475 Raptor.......... these have taken many a buffalo, hippo and elephant, not just by him, but many others. These have become the .510 caliber bullets to compare to

He is also a 577 NE fanatic as well, he did the same thing in .585 caliber with a 650 #13 Solid and matching 600 gr Raptor.

Also working early 2010 with some 2 band .585s

That touches some of the basics..............

 

[zephyr]

Here is the Barrel Strain Test michael458 mentioned.. because of his work I have been confidently shoot CEB Rapator's and Solids in my 1903 Gibbs 450NE with great terminal success on Buffalo and Tuskless

 

[steve white]

Do the CEBs also cut recoil as a result of easier passage? Or is that measurable.

 

[michael458]

Do the CEBs also cut recoil as a result of easier passage? Or is that measurable.

No.

 

[Nhoro]

Recoil is a result of accelerating the bullet to velocity. The weight of powder has an effect because it is also accelerated. So chamber pressure doesn't change the recoil but changing powder volume/ velocity etc may change both the recoil and the chamber pressure simultaneously. One is not causing the other, they are both controlled by other factors.

 

[zephyr]

Do the CEBs also cut recoil as a result of easier passage? Or is that measurable.

Here is a recoil calculator that you can play with

ShootersCalculator.com | Recoil Calculator

An online calculator that calculates the recoil energy, impulse, and velocity of a firearm according to the firearm's weight, powder charge, bullet weight, and bullet muzzle velocity.

shooterscalculator.com

you will see that bullet weight, powder volume, velocity and weight of gun are factored in