Understanding the different rate of barrel twists and most compatible projectiles

[HC]

You mean Contenders? If so I totally agree.

 

[drpatton]

You mean Contenders? If so I totally agree.

Renegades. I don't know anything about Contenders. I take it, all of the old T/C were that way?

 

[Greg_E]

Ok, I get the point, which reminded me of some testing Matt Dubber did with FX airguns. What he found was that you can over spin a pellet, and this over spin causes the pellet to gyrate around the center of the flight path. What's worse is that at long range you can get to a point where the spin that worked at 100 yards and 800fps is now too fast at 150 yards and 700fps. The rotation slows less with distance than forward velocity. I might be summarizing it wrong, but I think it was part of his Airgun 101 series on Youtube. Precession and nutation were the actual conditions and pretty sure it had to do with velocity and twist rate (or rpm).

 

[drpatton]

Ok, I get the point, which reminded me of some testing Matt Dubber did with FX airguns. What he found was that you can over spin a pellet, and this over spin causes the pellet to gyrate around the center of the flight path. What's worse is that at long range you can get to a point where the spin that worked at 100 yards and 800fps is now too fast at 150 yards and 700fps. The rotation slows less with distance than forward velocity. I might be summarizing it wrong, but I think it was part of his Airgun 101 series on Youtube. Precession and nutation were the actual conditions and pretty sure it had to do with velocity and twist rate (or rpm).

I don't know anything about Dubber or Airguns, the the concept (physics) would be the same. My understanding is the rotation (spin) may deteriorate slightly over the flight of the bullet, but it isn't by much. Basically, it's negligible. Also, Precession is from not enough spin, the object begins to wobble. I had to look up "nutation." It's simultaneous spin and wobble.

Most of our problem with spin, is the malleability of lead. If someone wants to give a bullet more spin than is needed for accuracy, they are limited by the softness of the projectile. Therefore, one must deal with deeper grooves and lighter charges.

I didn't realize it until this discussion thread, but in a .54 the 1:48 twist is really a good conical twist. As long as the bullet isn't too long. It makes for a usable but poor RB twist.

 

[Patched]

Ok, I get the point, which reminded me of some testing Matt Dubber did with FX airguns. What he found was that you can over spin a pellet, and this over spin causes the pellet to gyrate around the center of the flight path. What's worse is that at long range you can get to a point where the spin that worked at 100 yards and 800fps is now too fast at 150 yards and 700fps. The rotation slows less with distance than forward velocity. I might be summarizing it wrong, but I think it was part of his Airgun 101 series on Youtube. Precession and nutation were the actual conditions and pretty sure it had to do with velocity and twist rate (or rpm).

A modern hand loaded 100gr bullet leaves the 2506 muzzle at 3400 fps from a 1:10 twist barrel…at 100 yds it has rotated only about 362 rotations with a rotational speed of approximately 244,800 rpms…

A .535 round ball atop a max charge of BP leaves the muzzle at 1900fps of a 1:72 twist barel…at 100 yds the ball has only rotated about 50 times with a rotational speed of approximately 19,000 rpms.

Both projectiles shed velocity relatively quickly but arrive rotating about as fast as when they left the muzzle…

Just a little extra something to illustrate what’s actually happening.

I’m a serious FX owner/air-gunner so I’m familiar with Matt Dubber and his videos…you’re not alone.

 

[drpatton]

A modern hand loaded 100gr bullet leaves the 2506 muzzle at 3400 fps from a 1:10 twist barrel…at 100 yds it has rotated only about 362 rotations with a rotational speed of approximately 244,800 rpms…

A .535 round ball atop a max charge of BP leaves the muzzle at 1900fps of a 1:72 twist barel…at 100 yds the ball has only rotated about 50 times with a rotational speed of approximately 19,000 rpms.

Both projectiles shed velocity relatively quickly but arrive rotating about as fast as when they left the muzzle…

Just a little extra something to illustrate what’s actually happening.

I’m a serious FX owner/air-gunner so I’m familiar with Matt Dubber and his videos…you’re not alone.

So, tell me more about Air Rifles?

 

[Greg_E]

What do you want to know? Lots of different classes, springers, pump, co2, precharged pneumatic. The PCP is where the real power is, all the way up to using helium for extreme velocities. That said, you can get 357 at or above 200 foot pounds, 457 around and above 300-350fpe (unmodifed), 510 up to 700fpe, 58 even more, and 72 up around or above 1000fpe. All of these shooting cast ammo. It's a rabbit hole, and not very cheap at these power levels. My Umarex Hammer is up to 700fpe, but 3 shots per fill. Similar results from Airforce in their 510 size. I'm not sure how many shots you can get from the AEA Zeus in either 58 or 72.

There are also a few smoothbore shotguns scattered around, one of the more powerful from Umarex in 20 guage.

You'll need a compressor of some style if you go PCP, that will run a few hundred to well over $1000 depending on duty cycle and volume of compressed gas.

Also of note, hunting may be difficult. Some states only allow up to small game. Some states have minimum energy and 45 or larger. Some states are just a very low (215fpe at muzzle) for big game (not enough in my opinion). Airgun Hunting Laws by State | Pyramyd Air

I would suggest looking through the gateway to airguns site, think you need to join to see all of the sections Airgun Forum | GTA International Airgun Forum | 17,332+ Members also Airgun Nation Airgun Nation

As I said, a very long rabbit hole to go down. But when things collapse, I can pump with a hand pump enough to refill after a shot or two, and take down deer with my cast ammo. No power needed, but a heck of a workout with the pump. My 357 is a little above 200fpe and 10 shots to empty, my 50 is only 3 shots and would be painful to pump after 2 shots, but good power and can shoot the Lee REAL after sizing down to .510. I think it is a 1:24 barrel, pretty sure my 357 is a 1:16 barrel.

If you are looking for squirrel and rabbit, then a 22 or 25 would get you in for a fairly cost effective price, and probably be completely hand pump friendly. But ammo is far more limited with 50/50 success in casting pellets.

 

[drpatton]

What do you want to know? Lots of different classes, springers, pump, co2, precharged pneumatic. The PCP is where the real power is, all the way up to using helium for extreme velocities. That said, you can get 357 at or above 200 foot pounds, 457 around and above 300-350fpe (unmodifed), 510 up to 700fpe, 58 even more, and 72 up around or above 1000fpe. All of these shooting cast ammo. It's a rabbit hole, and not very cheap at these power levels. My Umarex Hammer is up to 700fpe, but 3 shots per fill. Similar results from Airforce in their 510 size. I'm not sure how many shots you can get from the AEA Zeus in either 58 or 72.

There are also a few smoothbore shotguns scattered around, one of the more powerful from Umarex in 20 guage.

You'll need a compressor of some style if you go PCP, that will run a few hundred to well over $1000 depending on duty cycle and volume of compressed gas.

Also of note, hunting may be difficult. Some states only allow up to small game. Some states have minimum energy and 45 or larger. Some states are just a very low (215fpe at muzzle) for big game (not enough in my opinion). Airgun Hunting Laws by State | Pyramyd Air

I would suggest looking through the gateway to airguns site, think you need to join to see all of the sections Airgun Forum | GTA International Airgun Forum | 17,332+ Members also Airgun Nation Airgun Nation

As I said, a very long rabbit hole to go down. But when things collapse, I can pump with a hand pump enough to refill after a shot or two, and take down deer with my cast ammo. No power needed, but a heck of a workout with the pump. My 357 is a little above 200fpe and 10 shots to empty, my 50 is only 3 shots and would be painful to pump after 2 shots, but good power and can shoot the Lee REAL after sizing down to .510. I think it is a 1:24 barrel, pretty sure my 357 is a 1:16 barrel.

If you are looking for squirrel and rabbit, then a 22 or 25 would get you in for a fairly cost effective price, and probably be completely hand pump friendly. But ammo is far more limited with 50/50 success in casting pellets.

I don't hunt anymore, so It would be for fun and accuracy. But, my only experience is shooting BBs with an old Daisy. I don't want to cast ammo. I want it to be fun, not a chore.

I found these sites:
PCP Air Rifles | Airgun Depot
https://www.pyramydair.com/air-guns/rifles/pcp-rifleshttps://www.airgunmegastore.com/pcp-air-rifles/

 

[Greg_E]

Pyramid, Utah Airguns, Fox Air Power are a few good ones. I would also check out About — The Best Airgun owned by Troy Hammer, he is bringing some really nice Turkish guns, and custom work on those to where you will not be disappointed with power and accuracy.

At the top end of accuracy will be Daystate and FX (among a few others), you will of course pay for that. Brocock is also pretty high end, seems like the lower step to Daystate, but not that much lower. Brocock Atomic XR is one I'd like to get, and a few different Daystate. Just hard to shell out over $2000 for an airgun (any gun). You can go way up if you want Olympic class 10 meter target guns, way up. Crosman challenger might be good for 10 meter, but still going to be up around $700-$1000.

All that said, you might like Field Target in either open (up to 20 fpe) or sub 12fpe and that might get you in for a more reasonable amount of money. Greg's Guide to Field Target Shooting - Part One lots of good used guns that would do well in FT. I just noticed the author's name, that is not me, I'm not that good a shot.

 

[Patched]

So, tell me more about Air Rifles?

Greg..E covered the introduction to airguns pretty well.
I’m partial to accuracy. Precharged Pneumatic airguns can deliver the accuracy…but is a relatively expensive rabbit hole..I have several.

I personally enjoy shooting some obsolete Olympic competition airguns, some of which I’ve ”sporterized”, scoped and increased their pellet velocities. Self contained single stroke power plants deliver .04 inch groups at 10 meters (1/4 inch at 30 -40yds). These used guns can be had for $600-$700. Feinwerkbau 300s or Feinwerkbau 600,601,603 models…ridiculously fine triggers, impeccable top accuracy and German quality.

Feinwerkbau also made a break barrel spring powered FWB 127 that performs (surprisingly for a break barrel) almost as well as the FWB 300s.
I still see these for $450-$500.

Other practical affordable quality airguns (I would recommend for indoor or backyard shooting) would be Wauhrauch brand break barrel guns, particularly their model 30, or R9…$500 range.
Avoid all “magnum airguns” and anything at Walmart…
buy quality JSB or Air Arms pellets avoiding the cheapies…there are other quality affordable guns but German or British made guns won’t disappoint.

I even shoot a vintage Daisy 499 muzzleloader target BBgun.
Peep sighted it keeps all shots on a penny size bull at 20 ft.

 

[drpatton]

Pyramid, Utah Airguns, Fox Air Power are a few good ones. I would also check out About — The Best Airgun owned by Troy Hammer, he is bringing some really nice Turkish guns, and custom work on those to where you will not be disappointed with power and accuracy.

At the top end of accuracy will be Daystate and FX (among a few others), you will of course pay for that. Brocock is also pretty high end, seems like the lower step to Daystate, but not that much lower. Brocock Atomic XR is one I'd like to get, and a few different Daystate. Just hard to shell out over $2000 for an airgun (any gun). You can go way up if you want Olympic class 10 meter target guns, way up. Crosman challenger might be good for 10 meter, but still going to be up around $700-$1000.

All that said, you might like Field Target in either open (up to 20 fpe) or sub 12fpe and that might get you in for a more reasonable amount of money. Greg's Guide to Field Target Shooting - Part One lots of good used guns that would do well in FT. I just noticed the author's name, that is not me, I'm not that good a shot.

Thanks. That's a start

 

[drpatton]

Greg..E covered the introduction to airguns pretty well.
I’m partial to accuracy. Precharged Pneumatic airguns can deliver the accuracy…but is a relatively expensive rabbit hole..I have several.

I personally enjoy shooting some obsolete Olympic competition airguns, some of which I’ve ”sporterized”, scoped and increased their pellet velocities. Self contained single stroke power plants deliver .04 inch groups at 10 meters (1/4 inch at 30 -40yds). These used guns can be had for $600-$700. Feinwerkbau 300s or Feinwerkbau 600,601,603 models…ridiculously fine triggers, impeccable top accuracy and German quality.

Feinwerkbau also made a break barrel spring powered FWB 127 that performs (surprisingly for a break barrel) almost as well as the FWB 300s.
I still see these for $450-$500.

Other practical affordable quality airguns (I would recommend for indoor or backyard shooting) would be Wauhrauch brand break barrel guns, particularly their model 30, or R9…$500 range.
Avoid all “magnum airguns” and anything at Walmart…
buy quality JSB or Air Arms pellets avoiding the cheapies…there are other quality affordable guns but German or British made guns won’t disappoint.

I even shoot a vintage Daisy 499 muzzleloader target BBgun.
Peep sighted it keeps all shots on a penny size bull at 20 ft.

Thank you

 

[Greg_E]

Should mention that Daisy has a high accuracy BB rifle, my club has a youth league with these in the indoor ranges Daisy Model 499B Champion Competition Air Rifle - Daisy At five meters and steel BB you can safely shoot this in your house. If I ever find one of these used for a good price, I'm going to pick it up Crosman Challenger® - Crosman.com

 

[idahoron]

My use of air rifles is on a need basis. My home on the edge of town was being over run with skunks and Rock Chucks. I got a POS break barrel spring gun. After that came a few more POS spring guns to find a good one. I don't have the ability to use a PCP. No scuba shops close and I don't want to carry a refill tank while hunting.
I finally decided to get the best spring gun in the market. I got an Air Arms TX200 22cal. I put a Vortex Diamondback tactical 6-24x50 FFP scope on it. The mounts are BKL triple rings modified to never loosen up with vibration.
After shooting all my Chucks and skunks, the neighbor farmers all asked me to shoot chucks for them.
I have shot over 1800 rock Chucks in 5 years. At least 1200 of them have been with my air rifle. Some of these farms pay as much as 5 dollars per chuck.

 

[ETipp]

My use of air rifles is on a need basis. My home on the edge of town was being over run with skunks and Rock Chucks. I got a POS break barrel spring gun. After that came a few more POS spring guns to find a good one. I don't have the ability to use a PCP. No scuba shops close and I don't want to carry a refill tank while hunting.
I finally decided to get the best spring gun in the market. I got an Air Arms TX200 22cal. I put a Vortex Diamondback tactical 6-24x50 FFP scope on it. The mounts are BKL triple rings modified to never loosen up with vibration.
After shooting all my Chucks and skunks, the neighbor farmers all asked me to shoot chucks for them.
I have shot over 1800 rock Chucks in 5 years. At least 1200 of them have been with my air rifle. Some of these farms pay as much as 5 dollars per chuck.

Dang fine accuracy there!

 

[drpatton]

My use of air rifles is on a need basis. My home on the edge of town was being over run with skunks and Rock Chucks. I got a POS break barrel spring gun. After that came a few more POS spring guns to find a good one. I don't have the ability to use a PCP. No scuba shops close and I don't want to carry a refill tank while hunting.
I finally decided to get the best spring gun in the market. I got an Air Arms TX200 22cal. I put a Vortex Diamondback tactical 6-24x50 FFP scope on it. The mounts are BKL triple rings modified to never loosen up with vibration.
After shooting all my Chucks and skunks, the neighbor farmers all asked me to shoot chucks for them.
I have shot over 1800 rock Chucks in 5 years. At least 1200 of them have been with my air rifle. Some of these farms pay as much as 5 dollars per chuck.

Thank you. I also live within the Borough, but my back yard is 200' long and I thought I could use the space to shoot an air rifle. As I stated on an earlier reply, I never shot an air rifle other than a Daisy BB gun. This is all new to me.
I just looked up the Air Arms TX200 22cal. $780 without rings or scope. Is that a good price?

https://www.pyramydair.com/product/air-arms-tx200-mkiii-air-rifle?m=174#517

 

[michiganmuzzy]

buy quality JSB or Air Arms pellets avoiding the cheapies…there are other quality affordable guns but German or British made guns won’t disappoint

The Gamo Urban is made in the UK by BSA and is my favorite low cost pcp. .22 , JSB pellets, and a Burris USA 4x scope, is a skwirl killing machine. I use a hand pump and get a great upper body workout at the same time.

 

[idahoron]

Thank you. I also live within the Borough, but my back yard is 200' long and I thought I could use the space to shoot an air rifle. As I stated on an earlier reply, I never shot an air rifle other than a Daisy BB gun. This is all new to me.
I just looked up the Air Arms TX200 22cal. $780 without rings or scope. Is that a good price?

https://www.pyramydair.com/product/air-arms-tx200-mkiii-air-rifle?m=174#517

That's what they are going for now. Mine is a walnut version.
The Air Arms TX200 is super easy to rebuild. The two reasons I got it over the other high end guns was ease of rebuild and it was the rifle that won the most tournaments in the UK.
After 8000 rounds the gun failed to cock. I had a master rebuild kit on the shelf. It cost 65 dollars. It took 20 minutes and only normal hand tools. I rebuilt it and it is basically a new rifle, good for another 8000 rounds. Here are some pictures of new parts and old parts.

 

[Patched]

My use of air rifles is on a need basis. My home on the edge of town was being over run with skunks and Rock Chucks. I got a POS break barrel spring gun. After that came a few more POS spring guns to find a good one. I don't have the ability to use a PCP. No scuba shops close and I don't want to carry a refill tank while hunting.
I finally decided to get the best spring gun in the market. I got an Air Arms TX200 22cal. I put a Vortex Diamondback tactical 6-24x50 FFP scope on it. The mounts are BKL triple rings modified to never loosen up with vibration.
After shooting all my Chucks and skunks, the neighbor farmers all asked me to shoot chucks for them.
I have shot over 1800 rock Chucks in 5 years. At least 1200 of them have been with my air rifle. Some of these farms pay as much as 5 dollars per chuck.

I had similar skunk, rock chuck and Califonia Beecher ground squirrel issues here in western Nevada…I used a custom tuned (by me) Beeman R1/HW80…then upgraded to an FX Royale .22 regulated PCP…..and soon I was being asked to eliminate chucks and squirrels on the urban west side of Reno…I lost count but there were 100s.

Almost silent, accurate enough for head shots at 60 yds…by the time the TX200s proved themselves in the US market, I kept only the Feinwerkbau spring guns for that power plant..
If you have the money you won’t be disappointed with aTX200. They’re top tier in fit and finish and accuracy…

 

[GBG]

Round balls have the least requirement for spin stabilization and the least amount of bearing surface available for gripping the rifling…which I interpret as “use deep cut rifling at a very slow rate of twist”.

In practicality accuracy is maintained over a wider range of powder charges…including large charges…according to my experiences.

Thank you for stating with brief clarity in words what I was trying to point out with numbers in post 52.

A .535 round ball atop a max charge of BP leaves the muzzle at 1900fps of a 1:72 twist barel…at 100 yds the ball has only rotated about 50 times with a rotational speed of approximately 19,000 rpms.

Both projectiles shed velocity relatively quickly but arrive rotating about as fast as when they left the muzzle…

The .535 RB will have slowed to approximately 1100 fps, just 57% of the original MV, but 19,000 RPM maintains the balls stability and accuracy over this entire range of forward speed (and more). Thank you also for giving a brief, clear and better numerical example of what I was trying to express in post 52.