5,000 fps coyote rifle?

[BigJohnH]

As mentioned without going totally custom there is nothing moving that fast. Neck a .300 Win. Mag. Down to.224.

 

[codyadams]

Another thing I found was that even the mono metal bullets have problems at ultra high velocities/RPM because of the center of gravity even in the best of bullets Is never perfect and at the RPM they turn (Around 400,000 RPM)if you could make a bullet perfectly balanced It would have to be a solid shape (No hollow points) and that would render it useless for hunting. I consider 3800 to 4200 ft/sec to be blazing fast and more than enough to do anything that is needed.

My experiments were to see if there were any limiting factors in the pursuit of velocity, and at some point the problems out weigh the results in my opinion. I am fortunate to be able to experiment with/build my own rifles and then able to adjust or even re chamber to save the rifle and expense. My labor is free if it is something that I want to try on my rifles.

In my days, as a builder and a shooter, I have fallen into the high pressure trap and also the high velocity trap and have learned my lessons the hard way. Now I look for optimum velocity and maximum accuracy, I know that there are always compromises
But Zero problems and maximum fun is the order of the day now.

Again, Just my opinion based on my testing.

J E CUSTOM

Is there a balance of twist that you found to work? I know stability and rotational speed can be two different things, but if you got a twist that would stabilize just enough to maintain accuracy and reduce rotational speed, it may be possible? How much did you experiment with different twist rates?

 

[ntsqd]

Due to this thread I got curious about centripetal force acting on the bullet at that velocity. Suppose you had a bullet that was stable at 3000 fps, what twist would you want to hopefully duplicate that stability at 5000 fps? I'm intentionally ignoring all of the other factors in the reality of this and just looking at twist rate in an effort to duplicate projectile rpm. I've also noted the resulting RPM so if you had a desired rotational speed the twist can be chosen. It's a simple Excel file, but the forum won't allow that upload, so PM if you want it so you can evaluate at different speeds.

3k twist: 6.5
5k twist: 10.8
332308

3k twist: 7.0
5k twist: 11.7
308571

3k twist: 8.0
5k twist: 13.3
270000

3k twist: 9.0
5k twist: 15.0
240000

3k twist: 10.0
5k twist: 16.7
216000

3k twist: 11.0
5k twist: 18.3
196364

3k twist: 12.0
5k twist: 20.0
180000

3k twist: 13.0
5k twist: 21.7
166154

3k twist: 14.0
5k twist: 23.3
154286

3k twist: 15.0
5k twist: 25.0
144000

3k twist: 16.0
5k twist: 26.7
135000

3k twist: 17.0
5k twist: 28.3
127059

3k twist: 18.0
5k twist: 30.0
120000

Clearly this isn't the end-all, be-all solution but it does answer one of the questions.

 

[jrkotz]

Don't do it! It's a trap! Haha the hyper velocity game is one that'll eat endless amounts of dollars. I've been working on a 20 Dasher. Going from 6mm down to 20 Cal sucks, and so does fire forming.

You'll definitely want to go with a long barrel for a full burn of slow powder - 28-32" and a slow twist to keep pressure down. You're on to something with the hammer bullet idea, that'll eliminate the concern of over spinning.

I think for yotes, and going light for caliber - you may be better served with a 6mm. Necking brass down to 224 sucks. There's a few good 6mm hot rods out there already, and plenty of 6.5 options that would easily size down. Be prepared to turn your necks.

JE's advice is good. Anything around 4k is crazy fast. That's pushing the envelope, 5k is just asking for more complications.

I've always thought a 6-284 would be a good hot rod. Now that the PRC is out, maybe a 6 PRC would fit the bill; in a short action too.

Keep us updated!

 

[22Kreedmire]

My solution. 22 creedmoor or a 22-250ai. Close to same. 22 creed has brass so that saves barrel life fire forming. I've seen a couple guys running 53 Vmax at 4300fps sight in 1.5" high at 100 with a scope height of 1.64" like mine (I shoot 75's) that gives me 4.8" low at 400. .5" high at 300. 2.4" high at 200. Thas hold on fur and DEAD to 400. Simple. And if you mount your scope a little higher like 2.0 from bore centerline that'll give you even less drop at 400 from center but it will increase your highest point in the arc a little in the mid range (200-250). A 20 br with a 40vmax at 4200 will do close to the above. Experiment with ballistic programs and bullets at realistic speeds then experiment with scope height and zero height and you'll learn what will prob work and what won't. Pretty amazing what scope height alone will do for your max point blank range. Take 2 223's , one a bolt rifle with the scope low to the bore and 1 an AR with a typical 2.75" scope height from centerline. Both identical bullets and speed and zero height at 100 yards. The AR will have a farther point blank range ,but it does cost a little in the mid range (will be higher in the arc). Ballistic programs are my best friend and when you have a reputable one like mine (shooter) or AB or kestrel. You'll find that the solutions are accurate That's how I determine what rifle I wanna build sometimes. I enter the bullet I want at the velocity I want and see if it's worth it over a rifle I already have. Then I look for a cartridge that will do that velocity

 

[5gauss]

Agree throat erosion would be an issue...would have to keep an eye on it /accuracy

 

[Eagleye242]

I had a 220 Swift AI built with a 30" barrel and 1-16" twist. I could drive 40 grain bullets to 4550 fps but lost one in 5 jacketed bullets to blowup before the target. Accuracy started to go south due to throat erosion around 1200 rounds. Never tried monomental bullets, since they were not available at the time. The barrel was a Hart, IIRC. Dave.

 

[dk17hmr]

I have never seriously looked at hammer bullets. I just spent about 20 minutes on their website I might need to try them now. But I noticed they have 17 and 20 caliber also. What about a 17-250AI or 20-250AI I bet either one would hit 5k

 

[JASmith]

Subscribe to Ammoguide.com for a whole trove pf cartridges that will work.

Either get your own copy or find a buddy jthat can run QuickLoad. You will quickly be able to assess the feasibility of a cartridge if not listed on Ammoguide.

 

[jackhawaiian]

I know the "light and fast" isn't the best method for extreme long range, but that isn't what this is about. This is about hitting 5000 fps or dang close for having the farthest possible aim on fur range. Also, getting stupid fast speeds, just because. I would like to discuss how to get to 5000 fps. Also, I know it has already been done. Also, I know that barrel life will likely be 500-700 rounds. Maybe even less. Don't care. This also isn't going to be a 1000 yard rifle with these light bullets. I want 400+ yards of coyote point blank range, the more the better. I'm going to develop a load, zero it, and every shot fired after that will hopefully kill a coyote. Now that we got that out of the way....

In the coyote hunting I have done, if I have missed a shot it was for one of two reasons. Either I misjudged the range and hit high/low using my .223, or it took me too long trying to range a dog and put the dope in my rifle, and they moved off. The best results I have had has been with my 22-250 using 40 grain v-max pills around 4000 fps, zeroed at 300 yards, I could aim on fur out to about 350 or so on a dog. I would like to make that even farther.

This will be with a 22 cal, I think going up to 6mm will require a good bit more cartridge to get there, and going town to 20 cal or 17 takes away some energy potential. I want to use the 44 grain hammer hunter, as a mono it should hold together just fine and will do a number to coyotes. I plan on HBN coating these, maybe squeeze a little more speed out and hopefully improve the already short barrel life.

My initial thought is a 22-243 improved, quality brass is plentiful. But then I figured, it would be easier to put together a 22-284 and get a little more capacity, but would that even be big enough? Possibly a 22-284 improved? With proper powders and a 30" barrel of the proper twist, would 5,000 fps be attainable with an HBN coated 44 grain hammer?

What are thoughts? Any other ideas on how to get a 44 grain pill to 5,000 fps?

If you experiment with the shape of the venturi area of the neck of the case so the powder is not sandblasting your barrel you can lengthen the barrel life. Turn your own bullets out of brass and size them for your barrel with the coating applied. Sizing will be trial and error on too tight to too loose. Length of barrel? Long enough to burn powder and build pressure any more will rob speed. Play with the crown at the end of the barrel the shock wave on 5000 fps is critical to accuracy and needs to filmed with a high speed camera. If you can stabilize the shock wave, then higher speeds with accuracy are possible. Barrel diameter? because of heat build up, 2nd or follow up shots might not be accurate. So cooling vents on the barrel needed. Maybe even fins like a 2 stoke engine. Bullet length? short bullets will not stabilize, will they be accurate at 400yds ? maybe, will they be stabile not likely. The envelope that surrounds the bullet has to be looked at very closely, wind tunnel type experimenting so you can see the shape of the envelope. When you can stabilize the envelope then speeds will go up, look at the tip of the bullet experiment to change the shape of the envelope. How to make a wind tunnel? Use a make shift tent that you can shoot through, set your camera up to view the inside of the tent, fill the tent with Hollywood smoke or something similar. Have the camera start filming at trigger movement. So to make an accurate rifle at 5000fps and beyond? Rethink or create the parameters. Bullets have been handicapped and stopped at the 4000-5000 range for a long time because experimentation becomes expensive. To exceed where others have failed you have to think outside the box.

 

[J E Custom]

Is there a balance of twist that you found to work? I know stability and rotational speed can be two different things, but if you got a twist that would stabilize just enough to maintain accuracy and reduce rotational speed, it may be possible? How much did you experiment with different twist rates?

At first I tried a 1 in 15 twist rate after having trouble with bullet disintegration, I went to a 1 in 16 and that helped. I think a 1 in 17 or 1 in 18 might help but I started hitting the wall in accuracy with both with the bullets that seemed to hold together. This is when I tried the mono metal bullets and the fact that they held together did not have any Bering on the loss of accuracy. I also tried a 6 grove and a 3 grove barrel and found that the 3 grove was faster but harder on jacketed bullets at those speeds.

The problem with small light bullets is the bearing surface on the bullet body is very short and engraving it is difficult I even considered a gain twist barrel, but decided to cut to the chase and use it at it,s best Around 4600 to 4650.

My best combination was a 1 in 16 twist 3 grove barrel using the varmint 30 and 40 grain ballistic tips. (For some reason Nosler used heaver jackets on there varmint bullets) I assume that they planed to use them for pelt hinting.

The bullets that I turned did well but were worthless for hunting because they acted like a armor piecing bullet and pass through with little or no energy transfer. In several cases the game acted like they were not hit and I had to track them several hundred yards.

I hope this information helps.

J E CUSTOM

 

[Timnterra]

I think the 22 creedmoor or 22-250ai might be all you need. I'm getting a comfortable 3300fps with 88gr bullets out of a 20" barrel in my 22 creedmoor. Add 10" of barrel slow the twist from 7 to 14 or so and shoot 40gr mono bullets and you should be well into the plus 4K range. It will also save you a ton not having to develop stuff on your own.

 

[22Kreedmire]

I think the 22 creedmoor or 22-250ai might be all you need. I'm getting a comfortable 3300fps with 88gr bullets out of a 20" barrel in my 22 creedmoor. Add 10" of barrel slow the twist from 7 to 14 or so and shoot 40gr mono bullets and you should be well into the plus 4K range. It will also save you a ton not having to develop stuff on your own.

Yeah I'm Getting 3500 with 75eldm and they are FLAT. 25" tube. Shoot 50 or 53's or yeah maybe even 40's in a 12 twist and you'll be golden and it's proven already. 53 vmax would be my first choice. Then 50 nosler or 50 Vmax. Then 40 nosler/Vmax. Nosler has a solid base and are extremely tuff when it comes to holding together at insane speeds. Dad had a cheetah mk1 and shot 55 ballistic tips at 4300 No other bullet would hold together. And it was a 9 twist. Tuff tuff bullets

 

[Travis Buntin]

The is the 223 wssm running across the chronograph at 4700 fps