Extruder Barell
Hi Guys, had a thought today regarding barells. There was a company here in Australia in the early 90’s making extruder, or tapered bore barells for the .22LR rimfire. The idea was that the bullet was squeezed down from .22 to .20 or to .17 calibre on exit. This increased velocity by some margin, due to the higher pressure from the extruding process upon firing. These barells where made by Myra gunshop in Broken hill Australia. How effective they were i dont know in rimfire, there was someone in a forum saying they werent accurate. They have sinced ceased trading, i think the inventor died a while back. I even read the Germans had developed the idea in WW2 for there anti tank guns. The idea is sound, and does work, but aparently much too expensive to be practical. Anyway enough of the history of the idea, my thinking is would the same principle work in a PCP rifle? I have read that some of the .25 guys are getting pretty much the same velocities with heavier pellets in .25 as we get in .22 with much lighter pellets. Aparently the greater surface area of a .25 V a .22 makes the .25 more efficient. So if it where possible to make/buy a .25 barell that tapered to .22, or .177 would it generate higher velocitie by building up more pressure? I dont think there would be any problems with the pellet swaging down in the bore. I have been kinda thinking of ways to experiment with this idea, but tapering a bore is a big problem. I was thinking to take an old shitty .177 barell and bore the breech end to 5.5 and taper a forcing cone like in a shotgun. Any body have an idea that this will or wont work? or how it could be done? Imagine a .25 40gr pellet swaged down to .177 fired at around 1000FPS,i think the sectional density and BC would be awsome ! Any idea’s would be most welcome !
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No no, we’ll leave it up so everyone can see. 🙂 One day some other random person may have the same dumb idea and we can send him here as a reference.
😈 🙄 😛 😆
Ok guys, you win. If I have offended by asking stupid questions then I apologize.delete it if you like.
whats an airforce got 3000 psi max?
what powder burn at 30000-40000 psi?
hmmm
i wonder 🙄 🙄
Holy crap, that was a beer all over the monitor funny.. 😆 😆 😆 😆 😆
As has been said Muzza, fantastical forces required. It doesn’t take alot of thought to realise that. On top of all that, if the likes of Jerry says its pie in the sky, then it is. Period 😉
I have something to add to here!!
I have a 1895 German Mauser Built to the Hilt. The gunsmith that did the work talked me in to a a custom extruder barrel. So him being the expert and all What the hell why not.
Ok now after a few G’s into my rifle I get to go to the range. took me 2 weeks of shooting to figure out that this set up was just BAD (and not the “good bad). Rounds went every where. the only time it shot good was if I put round after round threw it and the barrel got hot. Then it was “OK” at best.
Lets just say it is back to the stock barrel !!! And now I can go out and take a one shot kill on ground hogs at 1000 yds, not shoot all day wondering were the next round would go.
I learned the $$$$ Way, Just my 2Cents on this
Oh it’s not just him. We all think your idea is really really stupid.
And by the way, you trying to kick jerry off the thread is really stupid. One of the few guys that even gave you some advice to show you how hard this was going to be, and you want him to go away. We all like jerry, cool guy. You on the other hand, are looking to try stupid ideas and you aren’t even taking the advice that was already given to you. No one minds people asking questions, but when you ask a question and ignore what you don’t want to hear it’s annoying.
No, you aren’t going to be able to do it. You won’t get the pellet out of the barrel. If you do, it’ll be going at 3fps and fall on your foot, and you’ll probably get 3″ groups on your foot.
Jerry, you misspelled advice. 😆
Jerry
I don’t know what’s crawled up your ass and died, but I simply asked a question. If you really believe the concept doesn’t work in a powderburner I suggest you do some research before you open your fucking mouth and start abusing people on a public forum where no one is an expert and we all throw around ideas. Honestly mate , take it easy people ask questions all the time on forums that’s what there there for. There Is no reason to be nasty just because YOU think someones idea is stupid.If you don’t like this thread fuck off and leave it alone!
Somebody somewhere mic’ed the bore on a barrel to determine the choke. Wasn’t it in the 1/1000ths or some such #? .25 to .177 😯
i can drill a 22 cal hole in a block of steel and then hack saw it in half for ya after it is in half i will cut a few groves to act a “powerbands”
ill do it for free 😆 😆
😆 😆 😆
So far, my “mold man” would rather stick needles in his eyes than do a .22. I’m working on him though… 😉
well said jerry
remind me not to piss you off also 😉
now about them .22 pellets are they up n runnin yet?
lol
J/K
dont shoot 😉 😆
Yes, the air velocity will increase exiting a tapered bore. UNLESS the fucking hole is plugged by a chunk of lead too damn big to go through!
I was trying to be polite but the truth is that expecting a PCP to extrude a slug and having anything good happen is about the dumbest fucking idea I’ve heard since the last time I heard a hillbilly say “hey, watch this!”
So, instead of arguing with the answers to your question and getting the physics wrong to boot; how about you go cut the heads off some .25 pellets and shoot the skirts though a .22? That will be about the greatest amount of “extrusion” you’re going to achieve, if that. Then, when you’re all done come back and tell us what velocity the .22 shot with a range of normal pellets and what the .25 skirts did. Then show us the accuracy you achieved with the “extruded” projectiles.
I told you to go try and size a .25 slug down to .22. That’s still good advise, especially since your idea of a 40gr .25 pellet coming out a .177 hole driven by a PCP reveals you have no fucking clue of the force required to make that happen.
So, instead of arguing all the stupid things you think might be possible, go try one of them!
Jerry
the Myra extruded round did work in increasing velocity. WW2 German anti tank guns did work, they increased the velocity of the round. Google Myra extruded or squeezebore guns. I am simply asking if the same principle could work in a pcp. They may not be practicle to manufacture as thr cost would be very high for a small gain in velocity. But having said that we in the airrifle pcp world are always striving for more! If the wAter velocity increases would the air velocity increase if we taper the valve or barell?
That’s right Knife. It’s also known as Bernoulli’s (sp?) principle. The water accelerates through the smaller passage but the pressure is reduced. Observing the phenomena also led to the idea of reduced pressure across a curved surface because the air has to accelerate and that produces lower pressure (lift) and that means airplanes are possible!
Muzza,
You seem to believe that all other things remaining the same, pinching the barrel will result in a smaller bullet going faster. That’s just not the case. Do some more research and you’ll find nothing else was equal… Extruding projectiles from barrels is not a lost art, it was an idea that didn’t work… for a bunch of reasons.
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I dont know if this is correct , but the Ein jun pellets are extremely tight fitting pellets, and we know the barrel is tapered to some extent .
So I think the principle is already at work here , only not to the extent of what you were saying .
the other thing about the ein juns is they really bite the rifleing well.with a lot more surface area like it was mentioned before.
I dont think the PCP has the power to squeeze down a solid pellet unless the pellet was made hollow with a smaller tip