06-15-2018, 05:46 PM
If innovation is the interest, and ignoring standards the practice; Then why not change both the barrel extension and bolt together, enabling a vastly enlarged dimensional scope in which to innovate?
First, I admit to a vast, blissful, ignorance in regards to much of the following as far as the engineering involved, but you asked so here I post.
I like innovation, it's what makes good things greater over time. I also like standards, as they set a benchmark with which to measure growth; and a drawing board to return to, when new discoveries and knowledge are gained.
I believe that any innovation regarding the bolt strength increases of the Grendel are more likely to come if we don't allow ourselves to be limited to the standard 5.56 Barrel extension dimensions.
Observations are:
1 - Barrel extensions are now almost exclusively sold already installed on barrels. (1a) It takes a competently experienced, trained, and equipped individual to fit an extension to a barrel; (1b) and the makers have elected (correctly, I think) to almost exclusively sell retail barrels with the extensions already installed.
2 - Grendel already requires you to change the bolt and barrel when changing an AR15 into that caliber.
3 - The biggest limiter to the lug size and extractor thickness claw isn't only chambering headspace, but also the interior spaces of the barrel extension into which the bolt must fit to engage battery.
4 - The use of Grendel specific barrel extensions adds no untoward end user or installer changes or difficulty, if all other variables are maintained. Additionally, it allows Grendel specific bolt lug design and number. (See 8)
5 - Adding material to the bolt lugs and extractor claw is a definite advantage for strength and potential longevity - in any platform.
6 - Existing metallurgy and test data paves the way for simple changes to dimensional variables in the system, already proving strength of material; life expectancy; function; and most of all acceptable change limits.
7 - If loaded correctly, and as designed and intended - I.E. within pressure limits - Grendel has proven to be utterly reliable and effective within reasonable safety margins as it currently exists. Failures at Grendel chamber pressures are more likely due to poor material choice, condition, and manufacturing processes than the bolt not being able to contain detonation properly. However, it is understood that reinforcing the bolt would add some insurance and ability to absorb some flaws in this system.
8 - A safety benefit is created by changing the bolt lug and extension together is permanent, effective removal of the possibility of incorrect bolt usage. This is the kind of innovation that could in the end prove the most beneficial.
9 - This forum, and community provide a unique opportunity to share in these design and testing costs as it allows the spreading of the initial investment over the participating members. The ability to share, open source, and add minds to the team being advantages not available to design and testing departments in normal business.
10 - The Grendel case is small. Many of the maximum allowable loads are already limited by case capacity. Pushing strength into the bolt above it's current design may or may not lead to additional performance, and this innovation should be taken weighted more for safety purposes than performance gains.
I am sure there are lots of incorrect observations in the above list, but this post is to expose and discuss ignorance and incorrect assumptions.
There's an age old adage that states "If it ain't broke, don't fix it." I agree. And the AR15 barrel extension is definitely proven, and pretty much bomb proof. Which brings up new points of contention for me, as I am sure it has for other, wiser men before me. Chief amongst which is that it's MUCH easier to change a broken extractor or bolt than a barrel extension.
There is a bolt strength benefit of removing material from the barrel extension in order to add material to the bolt, but it obviously comes at the expense of weakening the extension. There is a "right" medium to what can be added and subtracted, and this can only be proven after extensive, thorough, and expensive testing. I don't think that much material needs to be removed from the extension to give the bolt quite a bit of added strength.
CMMG HAS ALREADY PAVED THIS ROAD WITH THEIR ANVIL, and GRENDEL PowerBOLT, but it does not lend itself to the major benefit of the original platform - parts availability, and interchangeability of the AR15.
First, I admit to a vast, blissful, ignorance in regards to much of the following as far as the engineering involved, but you asked so here I post.
I like innovation, it's what makes good things greater over time. I also like standards, as they set a benchmark with which to measure growth; and a drawing board to return to, when new discoveries and knowledge are gained.
I believe that any innovation regarding the bolt strength increases of the Grendel are more likely to come if we don't allow ourselves to be limited to the standard 5.56 Barrel extension dimensions.
Observations are:
1 - Barrel extensions are now almost exclusively sold already installed on barrels. (1a) It takes a competently experienced, trained, and equipped individual to fit an extension to a barrel; (1b) and the makers have elected (correctly, I think) to almost exclusively sell retail barrels with the extensions already installed.
2 - Grendel already requires you to change the bolt and barrel when changing an AR15 into that caliber.
3 - The biggest limiter to the lug size and extractor thickness claw isn't only chambering headspace, but also the interior spaces of the barrel extension into which the bolt must fit to engage battery.
4 - The use of Grendel specific barrel extensions adds no untoward end user or installer changes or difficulty, if all other variables are maintained. Additionally, it allows Grendel specific bolt lug design and number. (See 8)
5 - Adding material to the bolt lugs and extractor claw is a definite advantage for strength and potential longevity - in any platform.
6 - Existing metallurgy and test data paves the way for simple changes to dimensional variables in the system, already proving strength of material; life expectancy; function; and most of all acceptable change limits.
7 - If loaded correctly, and as designed and intended - I.E. within pressure limits - Grendel has proven to be utterly reliable and effective within reasonable safety margins as it currently exists. Failures at Grendel chamber pressures are more likely due to poor material choice, condition, and manufacturing processes than the bolt not being able to contain detonation properly. However, it is understood that reinforcing the bolt would add some insurance and ability to absorb some flaws in this system.
8 - A safety benefit is created by changing the bolt lug and extension together is permanent, effective removal of the possibility of incorrect bolt usage. This is the kind of innovation that could in the end prove the most beneficial.
9 - This forum, and community provide a unique opportunity to share in these design and testing costs as it allows the spreading of the initial investment over the participating members. The ability to share, open source, and add minds to the team being advantages not available to design and testing departments in normal business.
10 - The Grendel case is small. Many of the maximum allowable loads are already limited by case capacity. Pushing strength into the bolt above it's current design may or may not lead to additional performance, and this innovation should be taken weighted more for safety purposes than performance gains.
I am sure there are lots of incorrect observations in the above list, but this post is to expose and discuss ignorance and incorrect assumptions.
There's an age old adage that states "If it ain't broke, don't fix it." I agree. And the AR15 barrel extension is definitely proven, and pretty much bomb proof. Which brings up new points of contention for me, as I am sure it has for other, wiser men before me. Chief amongst which is that it's MUCH easier to change a broken extractor or bolt than a barrel extension.
There is a bolt strength benefit of removing material from the barrel extension in order to add material to the bolt, but it obviously comes at the expense of weakening the extension. There is a "right" medium to what can be added and subtracted, and this can only be proven after extensive, thorough, and expensive testing. I don't think that much material needs to be removed from the extension to give the bolt quite a bit of added strength.
CMMG HAS ALREADY PAVED THIS ROAD WITH THEIR ANVIL, and GRENDEL PowerBOLT, but it does not lend itself to the major benefit of the original platform - parts availability, and interchangeability of the AR15.
Nothing kills the incentive of men faster than a healthy sense of entitlement. Nothing kills entitlement faster than a healthy sense of achievement.