.172 Build

[YEMX]

Tiny, yes.... but quite destructive....



That is the HP version at ~ 1000 fps....

Bob

THAT is the exact reason .172 is so interesting to me!  Very small lead expenditure for each slug, and very destructive on targets.  I may have one cavity HP'd, and keep one as a solid... 

[Back_Roads]

 Yup and you can carry 100 rounds with you  without walking lopsided. 

[YEMX]

THE .172 IS HOME!!!!  Whew!  This thing is HEFTY!!  I'll post pics when I assemble it.  For now, it simply looks like a Condor SS with a longer (and THICK) barrel.  It even has a factory metal tank!  LOL  I did add a WOKButt though.  TBH, I think I'm just going to keep it this way and simply shoot it.  Not sure what scope I want yet.

[YEMX]

Was finally able to get a WOK Guard for this rifle.  I've also got a grip I want to try on this build as well...  I hope it'll work out.  If not, no biggie.  I think the good 'ol Enhanced Vertical Grip by Masterpiece Arms should work, no problem...

I've also got one of those roller bearing triggers by RMP Airguns.  I really want one of their chassis, but I have no idea when it's going to be out.  Hence why I went with the WOK Guard...

I still have to send my mold to Erik.  I've just emailed him again, if I don't get an email back within a few days, I'll give him a call.  I have this .172 mold and a 6mm mold I want HP'd. 

[bear air]

Man you are smashing projects this year Tom. Can't wait to see how it shoots.

[Pellethuntr]

Because my desire was to utilize the higher pressure capability. It’s obvious that would take a really fast twist/heavy pill. Which is difficult to find and $ for an experiment.

Sure I could reg it down but then I have other platforms I could do that with. If I stumble on to a faster twist, I’ll get my hopes up again.

Duy is gonna send me some slugs to try in my barrel. I’ll go ahead turn my barrel to fit but it’ll probably go on one of my regged platforms.

Dave

Dave, if you are shooting slugs instead of pellets couldn't you go supersonic with this gun?

[YEMX]

HA!!  So I forgot I have a top-mounted bipod, and I'd like to use it.  Except it's for a Pic rail...  ALL of my dovetail to pic rail adapters are too tall (I feel).  So I went on the hunt for a low profile adapter.  I found one made my NCStar, which looks pretty low.  We'll see how it goes.  I don't want it TOO low, because I'm worried I'll loose too much of my cant movement (bipod cants and swivels).  I also found a longer pic to dovetail insert adapter.  The way the bipod base is designed, I need an adapter that's got at least 3 grooves...  So your typical pic to dovetail adapters for scope rings won't work.  I feel like if it's TOO low (i.e. with one of these inserts), that I'll lose cant movement.  Again, I'm hoping the NCStar adapter is low enough... 

Not much of an update, I'll post some pics when I get these parts in and get them on the gun.

I've also ordered a new LDC for this gun from DonnyFL.  I wanted something built like a tank, since this rifle will be mostly travelling.  It's kind of a different LDC- it's for FX guns apparently- it's similar to the Tanto- except it's got a larger O.D.  Tanto is: 1.22"x5" FX: 1.36"x5".  It's got 1/2-20 threads.  It's $20 more than the Tanto, so $120.  I wanted the tank because I feel like the muzzle blast from this build will be pretty brutal (especially over time), and I'm not wanting to buy another LDC any time soon.  Also, it's good up to .25.  I did want to get the larger O.D., maybe it'll help with sound dissipation over the Tanto.  Maybe not though- NOW I notice that the Tanto has dedicated .177/.22 bores, vs the FX one, where it's .22/.25.  It's a good thing I don't need THAT much sound suppression since I'll be outside, in a open field 

Again, I'll post pics when I get this more assembled.

[rsterne]

Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....



You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... 

Bob

[Precision Action]

Tiny, yes.... but quite destructive....



That is the HP version at ~ 1000 fps....

Bob

Tiny, yet very impressive.

Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....



You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... 

Bob

2500fps? Wow-wee, that is getting up into high-powered rifle territory. Fascinating, not really practical for an air rifle, but fascinating.  Subsonic and Supersonic aerodynamics are so completely different.

[Pellethuntr]

Brian, going Supersonic will INCREASE the wind drift compared to keeping it in the 900s.... This is because of the huge drag increase in the Transonic region, which applies to all projectiles....



You would have to push a typical .172 slug at about 2500 fps before the drift is less than at 900 fps.... 

Bob

Bob your wind drift graph doesn't show wind angle or MPH?

[rsterne]

Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....

Bob

[Pellethuntr]

Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....

Bob

My apologize Bob, I am a first and foremost a hunter and have no interest in shooting pellets or slugs at 200 yards or even 100 yards. I am more interested in the terminal ballistics and the wound/expansion that can be created with a supersonic slug.

I believe that Dave's gun can send a projectile of this size well past super sonic and keep it there well past the distance I would want to hunt with it.

[Spacebus]

Correct, but it would have been 90 deg. to track, constant wind velocity from muzzle to target, and likely 10 MPH.... It doesn't make any difference to the relative performance, it is the sideways wind component that matters, and drift is proportional to that.... The point is to show the effect of muzzle velocity on the drift at 200 yards....

Bob

My apologize Bob, I am a first and foremost a hunter and have no interest in shooting pellets or slugs at 200 yards or even 100 yards. I am more interested in the terminal ballistics and the wound/expansion that can be created with a supersonic slug.

I believe that Dave's gun can send a projectile of this size well past super sonic and keep it there well past the distance I would want to hunt with it.

What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.

[Pellethuntr]

What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.

Nothing "requires" it. I have killed thousands of squirrels and other small game with a .22 pellet at 850 fps. But why not have the wound channel that a super sonic slug can offer? I am a big fan of over kill.

That's like saying why would I hunt deer with a rifle if my shot opportunities are rarely over 100 yards. A slug out of a shotgun does just as well at that range. I have killed lots of deer with a shotgun slug. I prefer what a rifle can do.

[Spacebus]

What would you be hunting that requires a 25+ grain slug to go supersonic? The whole benefit of sending smaller slugs super sonic is to retain energy and accuracy at long ranges. I think Bob is trying to say that there is no benefit of sending tiny slugs at super sonic velocities compared to a slightly larger/heavier slug at sub sonic speeds.

Nothing "requires" it. I have killed thousands of squirrels and other small game with a .22 pellet at 850 fps. But why not have the wound channel that a super sonic slug can offer? I am a big fan of over kill.

That's like saying why would I hunt deer with a rifle if my shot opportunities are rarely over 100 yards. A slug out of a shotgun does just as well at that range. I have killed lots of deer with a shotgun slug. I prefer what a rifle can do.

Are you hunting deer with a .172? I'm just not sure, beyond long range target shooting, what advantage there would be to a supersonic .172 slugs, especially when talking about airguns. I'm really not sure how much different the wound channel on a .172 traveling supersonic vs a 19 grain .22 pellet traveling at 750 - 900 FPS in the context of hunting small game. Maybe it would be useful for shooting Coyote at 100 yards, but at that point I would be switching to larger slugs with better BC values and more retained energy downrange.

I just don't see any advantage to hunting small game with a super sonic .172 slug. There are other applications where I could see it being useful, just not hunting small game.

[Pellethuntr]

Are you hunting deer with a .172? I'm just not sure, beyond long range target shooting, what advantage there would be to a supersonic .172 slugs, especially when talking about airguns. I'm really not sure how much different the wound channel on a .172 traveling supersonic vs a 19 grain .22 pellet traveling at 750 - 900 FPS in the context of hunting small game. Maybe it would be useful for shooting Coyote at 100 yards, but at that point I would be switching to larger slugs with better BC values and more retained energy downrange.

I just don't see any advantage to hunting small game with a super sonic .172 slug. There are other applications where I could see it being useful, just not hunting small game.

I guess we can all agree to disagree. My thoughts apply to Dave's gun anyway. Back to your regularly scheduled program!

[Ribbonstone]

Really have no right to an opinion...didn’t continue with the .172” slug experiments long enough.

But I can (repeat) tell you want I was after.

Trajectory and wind age advantage, energy was just a by product.

Accuracy is always “king”…..but for hitting the mark you are aiming at (paper targets, spinners, or little critters that don’t need much power), there is a high value in less wind age and less exacting range estimation (trajectory)….which is what slugs higher BC slugs do,

Could get the same effect wind age and trajectory with a bigger caliber/heavier slug of the same BC and earn more energy, which is likely what a hunter wants,  Didn’t see the  energy advantage in “hitting” and inanimate target; should be an advantage in “killing” and animate target.

Same BC slugs (regardless of caliber/weight) at the same speed gives the same trajectory, wind...so same hold… bigger/heavier slugs carries a lot more energy (at the same speed is proportional to weight).

If shooting paper, where is the advantage for an energetic hole in paper? Get bonus points for fiipping a spinner 8 times around rather than just 4?  Knocking a gong off it’s chains rather than just ringing it?


Consider:

The air tank/tube contains all the energy you get to shoot from. Each shot subtracts that shot’s energy the total supply of energy.  IF 40 foot pound “bites” of energy gives the same trajectory/windage as 80 foot pound bites, should be able to shoot 2X as much on the same air supply.

In the negative category, the smaller the slug, the more small imperfections count against accuracy.  Even if you start “perfect”,  imperfections can be induced by the act of firing (what exits the barrel may not be quite what was loaded into the barrel).

[darkcharisma]

OP wont take a picture without full accessory. keep us in suspense and OP thinks without accessories the gun wont look as good?

and i am getting lost in reading ribbonstones explainations. i am guessing accuracy might be affected with increased speed? is that your point? i may agree with that.

for pellethunter. the wound channel will likely look like what Bob showed with the expansion picture. bloody and quick death. its cool to over kill small pests if you hate them that much. but you may miss more due to possible accuracy with super sonic speed even below 100 yards?

I have shot .172 out of my Impact at 1050fps before. the slugs will track in a 3 inch circle down at 100 yards. sometimes hit exactly where i aimed. but sometimes 1-2 inches around the cross hair. i cant hit  a squirrel like that. I am pretty sure the wind was pushing it around like that.

[rsterne]

The external ballistics are only part of the story, of course.... Using air (ie not Helium), the closer you are to Mach 1, and particularly if you exceed it, the lower the efficiency.... In other words, it takes a LOT more air to get to 1200 fps than 1000 fps.... and even more to go faster.... The faster you drive the slug, the more air it takes for each FPE developed.... Supersonic, you are likely discharging a greater mass of air than that of the projectile....

The drag in the Transonic range is so large that the slug slows very quickly.... For example, a .22LR high-velocity RN drops below Mach 1 at about 75 yards, which is why the subsonic "target loads" outshoot them at 100 yards.... Add in the report, not only caused by all that extra air exiting the muzzle, but by the projectile itself creating shock waves from being Supersonic, and I see little point in wasting all the air required to get a couple of hundred extra fps, which you will lose before you get to 100 yards, and have more wind drift to deal with as well....

As you said, you are entitled to your opinion, I am just trying to offer you (and others) the science behind staying Subsonic to consider before deciding if it's worth it....

Bob

[Pellethuntr]

for pellethunter. the wound channel will likely look like what Bob showed with the expansion picture. bloody and quick death. its cool to over kill small pests if you hate them that much. but you may miss more due to possible accuracy with super sonic speed even below 100 yards?

I have shot .172 out of my Impact at 1050fps before. the slugs will track in a 3 inch circle down at 100 yards. sometimes hit exactly where i aimed. but sometimes 1-2 inches around the cross hair. i cant hit  a squirrel like that. I am pretty sure the wind was pushing it around like that.

That's exactly my point, Bob's picture showed a great wound channel, I want to know what that would look like at 1,500-1600 fps.

I guess my opinion is situational. I have a good size farm and I help manage another large farm near by. I am not usually concerned about shot count as my spare air is in the truck or on the ATV a close distance away. I probably average 10-15 shots at live targets on days I have time for it. My shooting is inside 40 yards. Statistically when you shoot at that many live targets you make human errors or in some situations it's out of your control and you make a bad shot. I would prefer to be packing as much damage as possible when those situations arise and minimize wounded critters. I could do all this with a 22lr but I enjoy airguns and it's almost impossible to find 22lr ammo for sale here.