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  #11  
Old 10-12-2017, 10:45 AM
HB of CJ HB of CJ is offline
 
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Default Commercially Available Plug? ...

Back in 1965, (am I THAT old?) there were commercially available aforementioned solid Carbine action plugs that did exactly what was alluded to? Shut off all gas and turned the Carbine into a straight pull repeating "bolt action" rifle. If memory serves.

Some rifle ranges back then required such. No high cap mags. No rapid fire. Pretty much just "sighting in" ranges. The instructions read that after removing the plug, reaming the gas port out with a .070 drill bit might be necessary? Too long ago.

Edited.

Last edited by HB of CJ; 10-12-2017 at 02:19 PM. Reason: edited
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  #12  
Old 10-12-2017, 12:22 PM
southfork southfork is offline
 
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That is what I would like to find an example of, HB. If I can't find one, maybe I can make one or have one made, now that I know the outer thread pattern of the piston nut. Thanks, everyone!
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  #13  
Old 10-12-2017, 12:34 PM
Cops504 Cops504 is offline
 
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the easiest thing to do is peen the nut against the piston. so you lose a nut, no big deal
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  #14  
Old 10-12-2017, 04:56 PM
ACampComLegacy ACampComLegacy is offline
 
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So, with such a modified Carbine, is the MV higher, with no gases' energy expended into cycling the action???????

How much more MV?
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  #15  
Old 10-12-2017, 05:17 PM
meplat meplat is offline
 
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Quote:
Originally Posted by ACampComLegacy
So, with such a modified Carbine, is the MV higher, with no gases' energy expended into cycling the action???????

How much more MV?
Yes, you could figure it out easily enough, though the estimate would be crude.

It's known from WW2 film studies, that the carbine recoil begins to cycle at about 27 feet/second. You know the mass of the bolt carrier assembly (on the order of a couple hundred grams) so you know the energy imparted by the piston on the slide assembly. Plugging the gas port means that this energy is now available for bullet travel. You know the bullet velocity of the unmodified carbine at the muzzle so you know its kinetic energy. Simply add this energy to that value and compute the bullet's new velocity.

I'll leave it to the reader to calculate numerically the expected change in bullet velocity.


Last edited by meplat; 10-12-2017 at 05:24 PM. Reason: SPOILER ALERT: The answer is "not much"
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  #16  
Old 10-12-2017, 06:52 PM
ACampComLegacy ACampComLegacy is offline
 
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Quote:
Originally Posted by meplat View Post
Yes, you could figure it out easily enough, though the estimate would be crude.

It's known from WW2 film studies, that the carbine recoil begins to cycle at about 27 feet/second. You know the mass of the bolt carrier assembly (on the order of a couple hundred grams) so you know the energy imparted by the piston on the slide assembly. Plugging the gas port means that this energy is now available for bullet travel. You know the bullet velocity of the unmodified carbine at the muzzle so you know its kinetic energy. Simply add this energy to that value and compute the bullet's new velocity.

I'll leave it to the reader to calculate numerically the expected change in bullet velocity.

I did the #'s, and I got ... ummm ...

Yeah - what did you get?
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  #17  
Old 10-12-2017, 07:00 PM
meplat meplat is offline
 
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Sorry, I don't do homework problems

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  #18  
Old 10-12-2017, 09:13 PM
ACampComLegacy ACampComLegacy is offline
 
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Default WTS; homework eatin' armadillo

Title says it all guys; son of a b^+*' ate my homework, and I forgot MV calculations for Carbine with gas port lockout

(except 'faster')
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