SA80 Replacement on the distant horizon ?

Interestingly the latest video up from Gun Jesus strongly infers that the L119A2 is not that popular vs the L119A1 so I do think Caracal/Haenal amongst others might have a good chance at the Ranger contract:
English lesson: You have inferred from what Gun Jesus was implying (if you can call flat-out statements that its intended users thought worse of the A2 than of the A1 merely 'implying' :-D )
 
Display of incomprehension follows:

Isn't 'force-chambering' exactly what the forward assist plunger on an AR is designed to do?
Yes :)
 
English lesson: You have inferred from what Gun Jesus was implying (if you can call flat-out statements that its intended users thought worse of the A2 than of the A1 merely 'implying' :-D )
I was being kind to the man...

Just in case he changes his mind at a later date :)
 
Because forcing a jammed round further forward makes so much sense
Oh, I agree, but we were discussing in the context of experiments with primary extraction.

The forward assist is basically Schrödinger's Jam button - it *might* help, or it *might* make the situation worse. If you've dropped the hammer and got a "click" it'll definitely make it worse (there's no out of battery safety on an AR15 so you can drop the hammer without the bolt carrier being fully forward, but it can only strike the primer when it is fully forward).

I share Karl and Ian's view on them to be honest.
 

gafkiwi

War Hero
Oh, I agree, but we were discussing in the context of experiments with primary extraction.

The forward assist is basically Schrödinger's Jam button - it *might* help, or it *might* make the situation worse. If you've dropped the hammer and got a "click" it'll definitely make it worse (there's no out of battery safety on an AR15 so you can drop the hammer without the bolt carrier being fully forward, but it can only strike the primer when it is fully forward).

I share Karl and Ian's view on them to be honest.
I got to speak to Carl Lewis (of LMT) when he was representing his company in its bid to replace the Steyr. He was of the opinion they were largely pointless but if he was to produce one without it would struggle to sell in the US Mil and Civi market because it wasn't the 'norm'.
The bolt assist on our MARS-L's isn't used for remedying IA's. We only use the bolt assist as part of press checks or quietly dropping the bolt when the situation requires it. I remember it also being a teaching or a tip if the rifle was submerged in the case of a water crossing or amphib work. The rifle was cocked just far enough for the round to break any seal in the chamber and let any excess water drain down out of the barrel and then the bolt assist used to close it.
 
I got to speak to Carl Lewis (of LMT) when he was representing his company in its bid to replace the Steyr. He was of the opinion they were largely pointless but if he was to produce one without it would struggle to sell in the US Mil and Civi market because it wasn't the 'norm'.
The bolt assist on our MARS-L's isn't used for remedying IA's. We only use the bolt assist as part of press checks or quietly dropping the bolt when the situation requires it. I remember it also being a teaching or a tip if the rifle was submerged in the case of a water crossing or amphib work. The rifle was cocked just far enough for the round to break any seal in the chamber and let any excess water drain down out of the barrel and then the bolt assist used to close it.
What do you know about the MARS-L with respect to whether the one piece upper receiver causes any problems for users? Forgotten Weapons did an episode recently on the L119A2 (Colt Canada) in which he said it was difficult to clean, the hand guard got hot, and other problems. Is that actually an issue with the LMT rifles?
 

gafkiwi

War Hero
What do you know about the MARS-L with respect to whether the one piece upper receiver causes any problems for users? Forgotten Weapons did an episode recently on the L119A2 (Colt Canada) in which he said it was difficult to clean, the hand guard got hot, and other problems. Is that actually an issue with the LMT rifles?
It's not an issue on the MARS-L because there is plenty of clearance around the barrel and gas tube and if anything manages to get stuck down there it only takes the loosening of one screw and removal of another to drop the whole barrel assembly out. I think the LMT design is more mature than the Colt one and a lot more user-friendly. Heat wise I had time on both the MARS-L and C8-IUR and other contemporaries and never noted an issue with heat transfer compared to the others. Cleaning wise I think it's more an inconvenience than an issue. Crap under the handguard won't stop the rifle working and to be honest in SOF hands it's most likely going to get blasted out with canned air or something in between tasks and checked when required by the unit armorers rather than being over-cleaned for a CO's parade. I found the H&K 416 more of a pain to clean since cleaning the gas parts required removing the entire handguard to access them.
Forgotten Weapons do some very informative videos but are from a very technical POV and based on the small window and environment they have to assess them. Priorities, needs, and care factors vary largely between military and civilians.
I've worked with Danes and none of them had or saw any issues with their Colts.
 
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TamH70

MIA
It's not an issue on the MARS-L because there is plenty of clearance around the barrel and gas tube and if anything manages to get stuck down there it only takes the loosening of one screw and removal of another to drop the whole barrel assembly out. I think the LMT design is more mature than the Colt one and a lot more user-friendly. Heat wise I had time on both the MARS-L and C8-IUR and other contemporaries and never noted an issue with heat transfer compared to the others. Cleaning wise I think it's more an inconvenience than an issue. Crap under the handguard won't stop the rifle working and to be honest in SOF hands it's most likely going to get blasted out with canned air or something in between tasks and checked when required by the unit armorers rather than being over-cleaned for a CO's parade. I found the H&K 416 more of a pain to clean since cleaning the gas parts required removing the entire handguard to access them.
Forgotten Weapons do some very informative videos but are from a very technical POV and based on the small window and environment they have to assess them. Priorities, needs, and care factors vary largely between military and civilians.
I've worked with Danes and none of them had or saw any issues with their Colts.

Karl and Ian do mud tests on In Range and fire thousands of rounds a year through various gats. I'd rate their knowledge of firearms and how they go bang and what stops them doing so way above mine because I didn't do anywhere near that amount of range time in eleven years of getting paid to wear green skin.
 

gafkiwi

War Hero
Karl and Ian do mud tests on In Range and fire thousands of rounds a year through various gats. I'd rate their knowledge of firearms and how they go bang and what stops them doing so way above mine because I didn't do anywhere near that amount of range time in eleven years of getting paid to wear green skin.
I also rate their knowledge and methods and have learned a lot from watching their videos. My only variation or differing of opinion is from experience in green and an understanding of the practical military context of small arms.
 

Themanwho

LE
Book Reviewer
In this instance we are looking for whether the extractor pulls back on the cartridge as the bolt rotates to the unlocked position. If it doesn't move the cartridge during that phase of the process then whether or not it can pull a stuck cartridge loose is irrelevant.
The extractor will not "pull back" on the fired case when the bolt rotates; the rotation is purely in the radial plane - there is no rearward travel. Correct cartridge headspace would mean that there should be a miniscule gap between the forward edge of the cartridge rim and the extractor - possibly just touching but with no force being applied, IIRC. The theory of the bolt rotation providing a form of primary extraction relies on the contact between the expanded case and the bolt face, nothing to do with the extractor (which only comes into play once the bolt is fully rotated and begins its rearward movement.

I reiterate I am inclined to support Stoaty's contention that the rotation doesn't provide primary extraction, primarily because of the larger surface area of cartridge expanded against the chamber walls which would have to be overcome by the smaller contact area of the bolt.

We're talking about a simple experiment to test one simple thing. If the cartridge doesn't move during that experiment then whether or not the cartridge was expanded by firing would be irrelevant.

If you really think it makes a difference then do the experiment I outlined using a fresh cartridge case and one from the same lot that had been fired once already and see if there is any difference.
The expansion of the cartridge is key to the theory, effectively providing an interference fit of the cartridge to the chamber and bolt face, which has to be broken by either primary or full extraction. In order to prove or disprove the theory the explosive expansion of the case should be part of any test, and simply placing a fired case in the chamber will not replicate the firing. For comparison, consider a nut and bolt, tightened beyond hand tight; if you undo the nut and then screw it back to its exact original "tightened" position, you will not have to use as much force to undo it a second time.

I also don't agree that machinist's bluing will show the evidence unequivocally as you are making indirect inferences rather than direct measurements. Inferences may be wrong as they are based on assumptions and what is wanted in this case is visual proof on video of the thing in question actually happening or not happening.
Using engineer's blue to mark a reference of whether a case has rotated or not can't be counted as inference in my book; it provides direct physical record of what's happened between the cartridge base and the bolt face, and common engineering practice (If a little old school :smile:). Otherwise I could equally argue that video evidence is reliant on human observation inferring what's happened, which would be equally silly...
 
The extractor will not "pull back" on the fired case when the bolt rotates; the rotation is purely in the radial plane - there is no rearward travel. Correct cartridge headspace would mean that there should be a miniscule gap between the forward edge of the cartridge rim and the extractor - possibly just touching but with no force being applied, IIRC. The theory of the bolt rotation providing a form of primary extraction relies on the contact between the expanded case and the bolt face, nothing to do with the extractor (which only comes into play once the bolt is fully rotated and begins its rearward movement.

I reiterate I am inclined to support Stoaty's contention that the rotation doesn't provide primary extraction, primarily because of the larger surface area of cartridge expanded against the chamber walls which would have to be overcome by the smaller contact area of the bolt.


The expansion of the cartridge is key to the theory, effectively providing an interference fit of the cartridge to the chamber and bolt face, which has to be broken by either primary or full extraction. In order to prove or disprove the theory the explosive expansion of the case should be part of any test, and simply placing a fired case in the chamber will not replicate the firing. For comparison, consider a nut and bolt, tightened beyond hand tight; if you undo the nut and then screw it back to its exact original "tightened" position, you will not have to use as much force to undo it a second time.


Using engineer's blue to mark a reference of whether a case has rotated or not can't be counted as inference in my book; it provides direct physical record of what's happened between the cartridge base and the bolt face, and common engineering practice (If a little old school :smile:). Otherwise I could equally argue that video evidence is reliant on human observation inferring what's happened, which would be equally silly...

The standard Fuddlore is that "the extractor rotates the case in the chamber". Impossible for basic physics / mechanics, even in cases where there is a helical primary extraction (which is very rare in self-loaders).

This "The friction between the bolt face and the case head rotates the case in the chamber" is a new one, but is simply not physically possible for any actual case geometry.
 

Themanwho

LE
Book Reviewer
The standard Fuddlore is that "the extractor rotates the case in the chamber". Impossible for basic physics / mechanics, even in cases where there is a helical primary extraction (which is very rare in self-loaders).

This "The friction between the bolt face and the case head rotates the case in the chamber" is a new one, but is simply not physically possible for any actual case geometry.
The Fuddlore you refer to appears to be bolleaux to me - and I'd never heard that one before. Old Mr Bilborough (PBUH) posited that it was the case contact with the bolt causing the form of primary extraction , but as I said I agree with your POV.
 

TamH70

MIA
Anyone putting bets as to whether or not any new rifles we get actually work out of the gate, or will they be like the L85 pre-A1 and be held together mit spit und Kleenex and built on a Friday?
 

Cold_Collation

LE
Book Reviewer
Anyone putting bets as to whether or not any new rifles we get actually work out of the gate, or will they be like the L85 pre-A1 and be held together mit spit und Kleenex and built on a Friday?
Depends on the gate.

If the gate is in Kitchener, Herstal or Oberndorf am Neckar I'd be pretty confident.

A gate just outside a warehouse in South Wales, less so...
 

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