deerslayer Posted September 21, 2020 Report Share Posted September 21, 2020 Well I doubt anybody runs without a blish lock anymore but we do have an answer on what it does to the recoil... It absorbs it! If you refer to my previous post on recall all I did was replace the blish lock I have a 28 bolt set up then do the same test using the same recoil spring. Link to comment Share on other sites More sharing options...
TSMGguy Posted September 21, 2020 Report Share Posted September 21, 2020 What are the five small pieces of metal? Link to comment Share on other sites More sharing options...
giantpanda4 Posted September 21, 2020 Report Share Posted September 21, 2020 Actually it transfers it, not absorbs it! Had the lock not been de-earred (Van Gogh'ed?) the load path stays between the bolt face and the receiver thru the lock. The Van Gogh'ed lock allows all of the energy to transfer to the rear of the receiver where the .22 bullet was sitting in place of the buffer. Good work on creating a visual reference for what the bolt system actually does! Link to comment Share on other sites More sharing options...
The1930sRust Posted September 22, 2020 Report Share Posted September 22, 2020 So, a '21 actuator had less pressure at the rear? R Link to comment Share on other sites More sharing options...
deerslayer Posted September 22, 2020 Author Report Share Posted September 22, 2020 Excellent observation. Overall energy transferred to the whole receiver is the same, just spread out more or concentrated at the back. TSMGguy, The little pieces of metal are squished 22 lead bullets, and the other piece is a de-eared blish lock (or Van Gogh'ed... That's funny..). See previous post for details of the experiment. So yes the 21 had the least of all energy transferred to the back of the receiver. 1 Link to comment Share on other sites More sharing options...
ppgcowboy Posted September 22, 2020 Report Share Posted September 22, 2020 Is that because it is lighter, it being the actuator. Link to comment Share on other sites More sharing options...
giantpanda4 Posted September 22, 2020 Report Share Posted September 22, 2020 Well, Dan said "So yes the 21 had the least of all energy transferred to the back of the receiver."To clarify that (or really confuse it) , it means least amount of energy through the buffer to the back of the receiver. The buffer in his case was a .22 bullet. All of the energy goes thru the receiver at some point. Two issues here - Blish vs. VanGogh and 21 vs. 28. By taking the ears off, the Blish lock does nothing to connect the bolt group to the receiver mass - so the buffer (bullet) gets smashed a lot because that is the major load path (the spring being the other path).Add the ears and now the whole receiver system is accelerating back until the pressure drops and the lock disengages with the receiver. A lot of the force now has dissipated since the bullet exited the barrel. Remember energy is force x time. Force is mass x acceleration.So in the case of the 21 vs 28, the 21 actuator mass is less and that means it accelerates faster to the rear, but it encounters a stronger spring than the 28. Energy is the same, less mass but bigger spring means faster cycling and more energy going into the spring rather than the buffer as seen by the squished bullets. 1 Link to comment Share on other sites More sharing options...
The1930sRust Posted September 22, 2020 Report Share Posted September 22, 2020 Link to comment Share on other sites More sharing options...
rpbcps Posted September 22, 2020 Report Share Posted September 22, 2020 (edited) Well, Dan said "So yes the 21 had the least of all energy transferred to the back of the receiver."To clarify that (or really confuse it) , it means least amount of energy through the buffer to the back of the receiver. The buffer in his case was a .22 bullet. All of the energy goes thru the receiver at some point. Two issues here - Blish vs. VanGogh and 21 vs. 28. By taking the ears off, the Blish lock does nothing to connect the bolt group to the receiver mass - so the buffer (bullet) gets smashed a lot because that is the major load path (the spring being the other path).Add the ears and now the whole receiver system is accelerating back until the pressure drops and the lock disengages with the receiver. A lot of the force now has dissipated since the bullet exited the barrel. Remember energy is force x time. Force is mass x acceleration.So in the case of the 21 vs 28, the 21 actuator mass is less and that means it accelerates faster to the rear, but it encounters a stronger spring than the 28. Energy is the same, less mass but bigger spring means faster cycling and more energy going into the spring rather than the buffer as seen by the squished bullets. Mike,That is well explained, I appreciate that. Stay safeRichard Edited September 22, 2020 by rpbcps Link to comment Share on other sites More sharing options...
deerslayer Posted September 22, 2020 Author Report Share Posted September 22, 2020 From my other posting on this can you run the numbers to get the speed of impact of the various bolts? I've been too tired lately to dust off my physics... Well..a nine pound sledgehammer lifted up 6 inches squished the bullet down to 0.1295 inches... So we're talking 4.5 footpounds of energy to more than replicate the recoil force. Link to comment Share on other sites More sharing options...
giantpanda4 Posted September 23, 2020 Report Share Posted September 23, 2020 Not bad - but you make the assumption that the "squishing" is linear, and it ain't! We sure have invented some cool new engineering terms here! Link to comment Share on other sites More sharing options...
thirtyround Posted September 23, 2020 Report Share Posted September 23, 2020 Thank You Gentlemen for the time and effort here. I cant get enough of this subject, The Thompson just doesn't disappoint regardless of what one does with it. JB Link to comment Share on other sites More sharing options...
Adg105200 Posted September 26, 2020 Report Share Posted September 26, 2020 Interesting topic, and very interesting way using the bullet squish method to help visualize the forces! Andrew Link to comment Share on other sites More sharing options...
mnshooter Posted September 29, 2020 Report Share Posted September 29, 2020 Very interesting that the M1 and 28 have identical squishes.Would expect the blishless M1 would be much closer to the earless 28, everything else being identical. Also interesting: Blishless is not found in any dictionary. Did this forum produce a new word? Link to comment Share on other sites More sharing options...
Arthur Fliegenheimer Posted September 30, 2020 Report Share Posted September 30, 2020 If there were a firearm testing equivalent of Todd Osgood's Project Farm youtube videos, this subject would be a must see. The Missourian Osgood is adept at configuring systems to measure stresses on mechanical and non mechanical consumer items. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now