delisle AK concept

justashooter · October 14, 2008, 04:10

well, not really a delisle AK. something much simpler.

so i saw this guy's post on the AK board and it got me thinking:
http://www.akfiles.com/forums/showthread.php?t=39760

supposing a fellow was to take an AK kit converted to strait pull and add a brased on threaded cap to the base of barrel, and a tube of electrical conduit with both ends threaded, and a threaded cap that is o-ring sealed around the barrel OD at muzzle. in effect, creating a chamber around the barrel that can be easily dissasembled. supposing a guy was to drill a bunch of holes in said barrel, install said tube, pack it with greased steel wool, and thread on the end cap.

what kind of sound reduction would he get? is this worth paying $200 and getting fingerprinted for, assuming a fellow has already been fingerprinted for related stuff. of course, said fellow would make the conversion to strait pull as he indicated in the tail end of the thread if the reduction value could be expected to be significant enough to warrant the $200. with the strait pull, auto cycling and protrusions from barrel that would prohibit installation of such a tube would be eliminated.

seems like this kind of tube would be very cheap to make, but would not have the added effect of spiral baffles and 180* wave deformation, etc. no wipes to wear out, or baffels to machine and align. just a very easily replaced wet liner to extend the moment of sound expression. no intent to truely silence, or go subsonic, just to reduce the signature by delaying it. would such a design reduce an AK based 7.62X39 rifle to a level that it could be comfortably fired without hearing damage?

supposing said guy added brased on chamber seperator discs at stations along the length of barrel that the tube would slip over. how many chambers should he divide 14" into, and how much would this improve the sound reduction? should the chambers be progressively smaller towards muzzle, or barrel vents progressively larger in diameter? should he add the seperators by brasing and mount the barrel in lathe to precision turn, or can they be a little bit sloppy in the tube and still somewhat effective? would add some interest to the process of packing the chambers, but could be done, i suppose.

ideas on the actual sound reduction as applied with cans from 1.5 to 3" diameters and 14" effective length? number and diameter of holes to gain effective utilisation fo the various potential can diameters? ATF requirements for design details in submission of form 1 application? can the design be adjusted after form 1 is granted by an increase in tube diameter?

what is actually proposed in the form 1 application? a design including the specifics of the rifle and integral suppressor? is the rifle/suppressor combination the actual form 1 item, so the rifle serial number alone sufficient? i assume the maker (said guy) would also have to mark the gun in accordance with statute and regulation.

to simplify it, suppose we went with the 3" can X 14" length, 6 baffles at uniform intervals, baffles that were OD about .060 less than can ID, vents increasing in diameter from .040 to .080 towards muzzle, and greased steel wool. how much reduction in sound are we predicting, and how many rounds before re-packing is required? what velocity reduction should we expect when using standard surp ammo?

what easily acheived improvements to design could be made? if we start with an AMD65 12.5" barrel, and extend it with thin wall tube of same OD and increased venting within the suppressor, will we get better reduction than from a 16" bbl? this would allow a rather large expansion chamber into which to vent gas, i suppose. pack this area with fiberglass or steel wool and a screw on cap with projectile diameter +0.10" hole and shoot a bore extension through it?

on the subject of short barrels: since the silencer is integral to the gun, and the entire package is papered NFA, do we even need to consider the 16/26" rule? just how noisy would this little bugger be if we used a 12" barrel, and a 3" X 10" can over the barrel? would our barrel vent diameter increase? i suppose there is a principle of diminishing returns, but maybe not.

from the aspect of safety consideration: with the proposed design, will i blow the tube off of it's threaded end caps if too much gas is vented into it? prolly blow off the front cap, only, so more effect on target at close range. of course, but how easy is this to do?

too many variables in the equation. anybody help me out here?

jdmcomp · October 14, 2008, 06:45

Did not the Delisle use 45 acp at subsonic levels? Sound suppressors just don't seem to add a lot to a gun shooting supersonic bullets which give off a sonic boom as they move along.

Deltaten · October 14, 2008, 17:52

Hmmm...
I LUV "what-ifs"

Better pull that fmj and replace with a 300 some grain lead slug, adjust charge as needed for sub-sonic and swing away. If not, it would sound just like the overhead at FF '07 in the butts... *crack* thump !

Think: Ford 9n muffler ; not cherry bomb glasspacks

Call it a WOlf-whisperer"

Can ya get a type 7 for kitchen table experiments?
LOL

USMC 0341 · October 14, 2008, 19:52

I really do like "What if?'s" as well but, well, here are my thoughts on this.

Not sure just what the AK package brings to this. Not known for inherent accuracy - and the main thing it does bring is a reliable semi-auto action which this concept neuters.

Today's suppressor technology has improved so much further than anything that was available when the original DeLisle was put together - so much that I don't see a reason to pay $200 to go "retro" on that count. Kinda feels like wedging an old flat head Ford V8 into a Honda Accura.

To me the heart of the DeLisle concept was a good rifle action fitted to run subsonic pistol rounds to be as accurate and quiet as possible. If I were to forego the subsonic round I would choose a caliber which would at least give better accuracy than the 7.62X39mm generally delivers.

I know how a concept can bud and grow in my mind before I notice problems that should have stopped it right up front. I am not a recognized authority on this subject so you have little need to take any of this to heart - it is just my opinion and worth just what you paid for it.

justashooter · October 14, 2008, 21:34

the delisle is a vented 9" barrel and standard spiral supressor for the balance of the chute. i wasn't willing to work that hard, and don't want a silent gun, just a reduced report.

i am up to my ass in AK kits, and was looking for some off the wall project that would be made from a cheap kit and a little bit of nothing. that's just my style.

since reduction involves paper work and doesn't seem viable, anyway, maybe i'll go the other way and try to make a light strait pull with a whomping big radial brake on the front end, instead. pics when i'm done.

Artful · October 17, 2008, 00:21

Hmm sounds like you want 7.62x39 clone of 9x39 rifles...

VSS

VSK-94

justashooter · October 17, 2008, 01:07

i am familiar with the 9X39 sub-sonic. makes a neat sentry and dog killer. too much trouble and expense.

was really just looking for a project that would use cheap parts, be low maintinance, and would be quieter than a standard AK. would seem that it would be too much trouble to paper and add a credible silencer, the lifespan of which is short, at best.

thinking i will use an AMD kit, convert the original folding stock to galil profile, convert the action to strait pull, add a credible scope base, and convert an extended AMD brake to recoil reducing type.

the fellow who built the concept rifle referenced remarks that recoil is significantly increased in the conversion to strait pull, and has added a bunch of mass, getting his gun up to 11 pounds. i would go for a light weight conversion, and depend on the recoil reducing brake to make it shootable. think that joining the side vents by opening up the space between them from 10 to 2 oclock and adding some 3" diameter fender washers swedged into 15-20 degree cones would give a serious reduction, as well as blowing the hat off of anybody within 10 feet.

Artful · October 18, 2008, 21:58

I'd think just use the 7.62x39 with heavy bullets - like the 182 grn for the 7.62x54R .311 bullets would give you a nice quiet round. As for making a suppressor Form 1 build - unless you built it wrong it should last as long as the barrel. - If you encapsulated the gas it would keep the sound within reason. Actually with a good volume suppressor AK's don't sound too bad.
Here's someone's Form 1 can on an AK

Subsonic - 6 grains of Reddot with 180 grain bullet
http://uk.youtube.com/watch?v=YeKquXp8gKY

you get the Idea.
They can be made to cycle with different loading
http://uk.youtube.com/watch?v=gc6980OYB6Y

full power regular supersonic
http://uk.youtube.com/watch?v=FHKU5ovRYe8

Still not to bad in the sound dept.

If you decide to go ahead with this - please take pictures of the project and post as I may want to do something like this with a AMD-65 kit I have awaiting assembly.

justashooter · October 19, 2008, 17:28

Quote:

Originally posted by Artful
I'd think just use the 7.62x39 with heavy bullets - like the 182 grn for the 7.62x54R .311 bullets would give you a nice quiet round. As for making a suppressor Form 1 build - unless you built it wrong it should last as long as the barrel. - If you encapsulated the gas it would keep the sound within reason.

If you decide to go ahead with this - please take pictures of the project and post as I may want to do something like this with a AMD-65 kit I have awaiting assembly.

a 182 would also dislocate my shoulder in a strait pull. i can see setting the bullets deep if the ogive allows. making it subsonic would also be a cinch.

USMC 0341 · October 19, 2008, 18:24

Quote:

Originally posted by justashooter

a 182 would also dislocate my shoulder in a strait pull.

If you load it to sub-sonic speeds it won't kick much more than a 40 S&W.

October 14, 2008, 04:10	#1
justashooter Registered FALaholic #: 5967 Join Date: Mar 2002 Location: york, pa. Posts: 4,494	delisle AK concept well, not really a delisle AK. something much simpler. so i saw this guy's post on the AK board and it got me thinking: http://www.akfiles.com/forums/showthread.php?t=39760 supposing a fellow was to take an AK kit converted to strait pull and add a brased on threaded cap to the base of barrel, and a tube of electrical conduit with both ends threaded, and a threaded cap that is o-ring sealed around the barrel OD at muzzle. in effect, creating a chamber around the barrel that can be easily dissasembled. supposing a guy was to drill a bunch of holes in said barrel, install said tube, pack it with greased steel wool, and thread on the end cap. what kind of sound reduction would he get? is this worth paying $200 and getting fingerprinted for, assuming a fellow has already been fingerprinted for related stuff. of course, said fellow would make the conversion to strait pull as he indicated in the tail end of the thread if the reduction value could be expected to be significant enough to warrant the $200. with the strait pull, auto cycling and protrusions from barrel that would prohibit installation of such a tube would be eliminated. seems like this kind of tube would be very cheap to make, but would not have the added effect of spiral baffles and 180* wave deformation, etc. no wipes to wear out, or baffels to machine and align. just a very easily replaced wet liner to extend the moment of sound expression. no intent to truely silence, or go subsonic, just to reduce the signature by delaying it. would such a design reduce an AK based 7.62X39 rifle to a level that it could be comfortably fired without hearing damage? supposing said guy added brased on chamber seperator discs at stations along the length of barrel that the tube would slip over. how many chambers should he divide 14" into, and how much would this improve the sound reduction? should the chambers be progressively smaller towards muzzle, or barrel vents progressively larger in diameter? should he add the seperators by brasing and mount the barrel in lathe to precision turn, or can they be a little bit sloppy in the tube and still somewhat effective? would add some interest to the process of packing the chambers, but could be done, i suppose. ideas on the actual sound reduction as applied with cans from 1.5 to 3" diameters and 14" effective length? number and diameter of holes to gain effective utilisation fo the various potential can diameters? ATF requirements for design details in submission of form 1 application? can the design be adjusted after form 1 is granted by an increase in tube diameter? what is actually proposed in the form 1 application? a design including the specifics of the rifle and integral suppressor? is the rifle/suppressor combination the actual form 1 item, so the rifle serial number alone sufficient? i assume the maker (said guy) would also have to mark the gun in accordance with statute and regulation. to simplify it, suppose we went with the 3" can X 14" length, 6 baffles at uniform intervals, baffles that were OD about .060 less than can ID, vents increasing in diameter from .040 to .080 towards muzzle, and greased steel wool. how much reduction in sound are we predicting, and how many rounds before re-packing is required? what velocity reduction should we expect when using standard surp ammo? what easily acheived improvements to design could be made? if we start with an AMD65 12.5" barrel, and extend it with thin wall tube of same OD and increased venting within the suppressor, will we get better reduction than from a 16" bbl? this would allow a rather large expansion chamber into which to vent gas, i suppose. pack this area with fiberglass or steel wool and a screw on cap with projectile diameter +0.10" hole and shoot a bore extension through it? on the subject of short barrels: since the silencer is integral to the gun, and the entire package is papered NFA, do we even need to consider the 16/26" rule? just how noisy would this little bugger be if we used a 12" barrel, and a 3" X 10" can over the barrel? would our barrel vent diameter increase? i suppose there is a principle of diminishing returns, but maybe not. from the aspect of safety consideration: with the proposed design, will i blow the tube off of it's threaded end caps if too much gas is vented into it? prolly blow off the front cap, only, so more effect on target at close range. of course, but how easy is this to do? too many variables in the equation. anybody help me out here? __________________ If the concept of heading on down to the local Home Depot and transforming $100 worth of random pipe bits into a killing machine doesn’t appeal to you, you’re a frikkin' pansy. Also, you’re probably sane and will live significantly longer than I will. Nonetheless you disgust me, and I take comfort in the knowledge that your obituary will be nowhere near as humorous as mine. The next time I hear "THE RANGE IS NOW HOT", it just wont be the same. Max tried another question. "What sort of people live about here?" "In THAT direction," the Jin said, waving its right paw round, "lives a Han: And in THAT direction," waving the other paw, "lives a Ming Hare. Visit either you like: they're both mad." "But I don't want to go among mad people," Max remarked. "Oh, you can't help that," said the Jin: "we're all mad here. I'm mad. You're mad." "How do you know I'm mad?" said Max. "You must be," said the Jin, "or you wouldn't have come here." Last edited by justashooter; October 14, 2008 at 04:17.

October 14, 2008, 17:52	#3
Deltaten Registered FALaholic #: 124 Join Date: Jul 2000 Location: Lancaster, PA USA Posts: 8,498	Hmmm... I LUV "what-ifs" Better pull that fmj and replace with a 300 some grain lead slug, adjust charge as needed for sub-sonic and swing away. If not, it would sound just like the overhead at FF '07 in the butts... crack thump ! Think: Ford 9n muffler ; not cherry bomb glasspacks Call it a WOlf-whisperer" Can ya get a type 7 for kitchen table experiments? LOL __________________ All or Nothing! Senator McCarthy was right! and as always......FYB!

October 14, 2008, 21:34	#5
justashooter Registered FALaholic #: 5967 Join Date: Mar 2002 Location: york, pa. Posts: 4,494	the delisle is a vented 9" barrel and standard spiral supressor for the balance of the chute. i wasn't willing to work that hard, and don't want a silent gun, just a reduced report. i am up to my ass in AK kits, and was looking for some off the wall project that would be made from a cheap kit and a little bit of nothing. that's just my style. since reduction involves paper work and doesn't seem viable, anyway, maybe i'll go the other way and try to make a light strait pull with a whomping big radial brake on the front end, instead. pics when i'm done. __________________ If the concept of heading on down to the local Home Depot and transforming $100 worth of random pipe bits into a killing machine doesn’t appeal to you, you’re a frikkin' pansy. Also, you’re probably sane and will live significantly longer than I will. Nonetheless you disgust me, and I take comfort in the knowledge that your obituary will be nowhere near as humorous as mine. The next time I hear "THE RANGE IS NOW HOT", it just wont be the same. Max tried another question. "What sort of people live about here?" "In THAT direction," the Jin said, waving its right paw round, "lives a Han: And in THAT direction," waving the other paw, "lives a Ming Hare. Visit either you like: they're both mad." "But I don't want to go among mad people," Max remarked. "Oh, you can't help that," said the Jin: "we're all mad here. I'm mad. You're mad." "How do you know I'm mad?" said Max. "You must be," said the Jin, "or you wouldn't have come here."

October 17, 2008, 00:21	#6
Artful Registered FALaholic #: 10191 Join Date: Apr 2003 Location: arizona Posts: 2,160	Hmm sounds like you want 7.62x39 clone of 9x39 rifles... VSS VSK-94 __________________ I'm not Fat, just Tactially Padded

October 17, 2008, 01:07	#7
justashooter Registered FALaholic #: 5967 Join Date: Mar 2002 Location: york, pa. Posts: 4,494	i am familiar with the 9X39 sub-sonic. makes a neat sentry and dog killer. too much trouble and expense. was really just looking for a project that would use cheap parts, be low maintinance, and would be quieter than a standard AK. would seem that it would be too much trouble to paper and add a credible silencer, the lifespan of which is short, at best. thinking i will use an AMD kit, convert the original folding stock to galil profile, convert the action to strait pull, add a credible scope base, and convert an extended AMD brake to recoil reducing type. the fellow who built the concept rifle referenced remarks that recoil is significantly increased in the conversion to strait pull, and has added a bunch of mass, getting his gun up to 11 pounds. i would go for a light weight conversion, and depend on the recoil reducing brake to make it shootable. think that joining the side vents by opening up the space between them from 10 to 2 oclock and adding some 3" diameter fender washers swedged into 15-20 degree cones would give a serious reduction, as well as blowing the hat off of anybody within 10 feet. __________________ If the concept of heading on down to the local Home Depot and transforming $100 worth of random pipe bits into a killing machine doesn’t appeal to you, you’re a frikkin' pansy. Also, you’re probably sane and will live significantly longer than I will. Nonetheless you disgust me, and I take comfort in the knowledge that your obituary will be nowhere near as humorous as mine. The next time I hear "THE RANGE IS NOW HOT", it just wont be the same. Max tried another question. "What sort of people live about here?" "In THAT direction," the Jin said, waving its right paw round, "lives a Han: And in THAT direction," waving the other paw, "lives a Ming Hare. Visit either you like: they're both mad." "But I don't want to go among mad people," Max remarked. "Oh, you can't help that," said the Jin: "we're all mad here. I'm mad. You're mad." "How do you know I'm mad?" said Max. "You must be," said the Jin, "or you wouldn't have come here."

October 14, 2008, 06:45	#2
jdmcomp Registered FALaholic #: 8267 Join Date: Dec 2002 Posts: 660	Did not the Delisle use 45 acp at subsonic levels? Sound suppressors just don't seem to add a lot to a gun shooting supersonic bullets which give off a sonic boom as they move along.

October 14, 2008, 19:52	#4
USMC 0341 Registered FALaholic #: 988 Join Date: Sep 2000 Location: gpne Posts: 2,451	I really do like "What if?'s" as well but, well, here are my thoughts on this. Not sure just what the AK package brings to this. Not known for inherent accuracy - and the main thing it does bring is a reliable semi-auto action which this concept neuters. Today's suppressor technology has improved so much further than anything that was available when the original DeLisle was put together - so much that I don't see a reason to pay $200 to go "retro" on that count. Kinda feels like wedging an old flat head Ford V8 into a Honda Accura. To me the heart of the DeLisle concept was a good rifle action fitted to run subsonic pistol rounds to be as accurate and quiet as possible. If I were to forego the subsonic round I would choose a caliber which would at least give better accuracy than the 7.62X39mm generally delivers. I know how a concept can bud and grow in my mind before I notice problems that should have stopped it right up front. I am not a recognized authority on this subject so you have little need to take any of this to heart - it is just my opinion and worth just what you paid for it.

October 18, 2008, 21:58	#8
Artful Registered FALaholic #: 10191 Join Date: Apr 2003 Location: arizona Posts: 2,160	I'd think just use the 7.62x39 with heavy bullets - like the 182 grn for the 7.62x54R .311 bullets would give you a nice quiet round. As for making a suppressor Form 1 build - unless you built it wrong it should last as long as the barrel. - If you encapsulated the gas it would keep the sound within reason. Actually with a good volume suppressor AK's don't sound too bad. Here's someone's Form 1 can on an AK Subsonic - 6 grains of Reddot with 180 grain bullet http://uk.youtube.com/watch?v=YeKquXp8gKY you get the Idea. They can be made to cycle with different loading http://uk.youtube.com/watch?v=gc6980OYB6Y full power regular supersonic http://uk.youtube.com/watch?v=FHKU5ovRYe8 Still not to bad in the sound dept. If you decide to go ahead with this - please take pictures of the project and post as I may want to do something like this with a AMD-65 kit I have awaiting assembly. __________________ I'm not Fat, just Tactially Padded

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