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5/20/2026 11:29:46 PM EDT
[Last Edit: spydercomonkey][Edited]
As I had mentioned in 2 past threads, High Pressure Ammo seems to be the next evolution of the AR15.

https://www.ar15.com/forums/ar-15/Rumor-URGI-replacement-designed-for-High-Pressure-80kpsi-5-56/118-791849/?

https://www.ar15.com/forums/ar-15/100kpsi-5-56-75gr-3500fps-High-Pressure-future-of-AR15/118-792654/?

This is now official with the HICAR program; the rifle very much sounds like what we would hope to see in a "M4A2" - High pressure, good trigger, fully ambi, advanced coatings, MLOK, etc.

https://soldiersystems.net/2026/05/20/ussocom-seeks-hypervelocity-improved-capability-assault-rifle-hicar/



HICAR shall be compatible and capable of fit and functioning with the M4A1 lower receiver group without permanent modifications (T); with zero modifications (O)

HICAR shall fire and function with M855A1, Mk262 as well as Government supplied M855A1+ hypervelocity ammunition loaded to 82kpsi (T); with future hypervelocity ammunition designs optimized for projectile velocity and terminal effects on target (O).

HICAR barrel shall be between 11- 12 inches in length, measured from bare muzzle to bolt face (T=O).
...
Barrel life 8,000 (T); 20,000 (O) rounds.

Measured with M855A1+ ammunition fired as a function of Muzzle Velocity loss of 5% below mean or dispersion above an established threshold, whichever occurs first (T=O).
....
Ambidextrous bolt catch/bolt release, ambidextrous magazine release, and ambidextrous charging handle (O).

Fencing around the controls to prevent accidental engagement of the magazine release and bolt release mechanisms (T=O).
...
Protected with durable corrosion resistant coating in all SOF climatic environments including NBC contaminated environments. Corrosion and abrasion proof coatings to minimize the attraction of dust and contaminants (T=O).

Utilize where possible self-lubricating coatings and minimize buildup of dust, carbon, copper, and debris (O).


Biggest weakness in the program is sticking with the Gen 3 PMAG / AR15 2.25" COL cartridge spec, which prevents using a longer lower drag projectile that would really open up long range velocity retention.

Think a 5.56 version of the VLD projectile used in the new 6.8 NGSW:


A rifle based on the Six8 receiver (such as the SF ICAR) might have allowed for a "5.56 Long" loaded to 2.32" COL, both allowing a more VLD projectile shape and also preventing the newer high pressure 5.56 being chambered in legacy rifles. Although from the SSD article it sounds like the Army may want to convert all M4's to high pressure in the future.
5/20/2026 11:37:43 PM EDT
[#1]
Seemingly going along with this, PROOF is releasing a new barrel tech optimized for High Pressure cartridges:

https://soldiersystems.net/2026/05/20/proof-launches-new-barrel-technology/



In particular, a great deal of work was documented with testing of 7mm BC Peak Alloy case technology which showed barrel life of up to 2X that of conventional rifling. Working in conjunction with next generation defense grade alloys (GNB-200 and ARMAD) along with nitriding and chrome replacements will provide what PROOF describes as “a future proofed design with improved dispersion and longevity.”

Features:

Exceptionally long throat life with very uniform jump to rifling during the extended life of the barrel
Barrels don’t chase the lands on the more aggressive cartridges of today: 80KPSI 6.8×51, over bore 300NM or cartridges like 22CM
Lower projectile structural stresses
Reduced jacket damage
Reduced engraving forces
Understandably there has been some very vocal concern over barrel life when firing high pressure cartridges. They aren’t going away and I only expect their use to increase as we become more comfortable with increases muzzle velocity as well as the reliability of optimized firearms. The new PXT barrels may be the answer and have an added benefit of even higher velocity and accuracy.

This new barrel will also likely be an enabling technology at least for some offerers for the recently announced USSOCOM search for the Hypervelocity Improved Capability Assault Rifle (HICAR) firing high pressure 5.56mm ammunition.
5/20/2026 11:42:41 PM EDT
[#2]
I figured once we saw the M7's 2-piece case design we would eventually see that migrate to 5.56 ammo. The M7 has always seemed a step too far, but if you are able to improve the ballistics of standard 5.56 with minimal modifications that would end up being the cheaper, good enough option the military generally goes with.
5/21/2026 2:16:38 AM EDT
[#3]
I will be looking forward the results of both of these developments.

My hopes are high considering Proof Research has done a lot of the barrel work already.

FYI... a long but great video explaining Proof's work on the barrel.

Introducing… PXT - Proof Exponential Twist.
*Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them.*
JAFOM.... Just another fat old man.

________________________________

TOGC,IADC
5/21/2026 8:20:49 AM EDT
[#4]
Ill just stick with a 20" rifle
Do Good
Be Dangerous
Live Free
5/21/2026 9:07:07 AM EDT
[#5]
Quote History
Originally Posted By 03RN:
Ill just stick with a 20" rifle
View Quote


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.
5/21/2026 9:59:46 AM EDT
[#6]
Probably the case where 'special' is as in 'specialized' as opposed to 'exquisite'.
5/21/2026 10:30:33 AM EDT
[#7]
Quote History
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.
View Quote

Carrying around a huge musket is impractical. Even this HICAR thing is sort of silly when you look at modern near peer war in Ukraine where small arms account for only 14% of casualties.
5/21/2026 10:42:22 AM EDT
[#8]
Quote History
Originally Posted By 03RN:
Ill just stick with a 20" rifle
View Quote

With a suppressor?
5/21/2026 11:01:53 AM EDT
[#9]
Quote History
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.
View Quote

It seems really short to me as well, but maybe they are going that short on the assumption that it will always be suppressed whatever future can is in the works, so they are leaving room in terms of OAL.
5/21/2026 11:18:27 AM EDT
[#10]
I can only surmise that the short barrel requirement is taking into account full time use of a supressor, otherwise it does seem like a waste, trying to wring more velocity out of the round while at the same time shortening the launch pad.
5/21/2026 11:22:54 AM EDT
[#11]
We can't run the M-4 to its basic capabilities.  The average soldier, LEO, Marine, can't run the legacy rifle anywhere close to what it can do with a simple ACOG.  


We don't even pretend to train to that level or hold a standard approaching it.  


But, yeah...we should buy magic rifles.  


5/21/2026 12:04:28 PM EDT
[#12]
This is crazy. And not crazy in a good way.
This is...a clue - Pat_Rogers
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
5/21/2026 12:18:40 PM EDT
[#13]
I have a feeling a lot of bolt lugs are about to be sacrificed.
5/21/2026 12:33:42 PM EDT
[#14]
Quote History
Originally Posted By CheemsK1500:
I have a feeling a lot of bolt lugs are about to be sacrificed.
View Quote

It is all basically better new fangled space age materials.  But yeah, when something goes tits up, it could get ugly.
5/21/2026 12:37:03 PM EDT
[#15]
Quote History
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.
View Quote


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.
5/21/2026 12:44:04 PM EDT
[#16]
Originally Posted By panthermark:

It seems really short to me as well, but maybe they are going that short on the assumption that it will always be suppressed whatever future can is in the works, so they are leaving room in terms of OAL.
View Quote


If they go with a 6mm arc it'll be fine. I can hit my 10 in steel plate repeatedly with my 12 in arc at 650 yards.

Hunter Constantine was hitting a large plate at 1k yards with his 10.5

They should have just went with 6mm arc
5/21/2026 12:51:03 PM EDT
[#17]
Quote History
Originally Posted By JoeDevola:
I can only surmise that the short barrel requirement is taking into account full time use of a supressor, otherwise it does seem like a waste, trying to wring more velocity out of the round while at the same time shortening the launch pad.
View Quote

The requirements call out use of the contract HUX can with a note that they plan to open a separate buy for suppressors specifically.
5/21/2026 1:35:58 PM EDT
[#18]
Seems like PROOF is using gain twist rifling?  Not a new concept.   The brass case also limits the psi.  Brass flows at a lower temp than steel cases or the thin stainless cases being tried.  Wouldn't  mind one of their Barrels for my ar.
5/21/2026 2:03:20 PM EDT
[#19]
The obsession with short barrels is counterproductive. I'd rather see a 13.9 or 14.5 as standard, with a 16" DMR and 11.5" as special application receivers.
5/21/2026 2:17:01 PM EDT
[#20]
The reason for short barrels is reducing weight and size. Small arms aren't going to dominate a near peer conflict.
5/21/2026 2:59:38 PM EDT
[Last Edit: PacificNic][Edited] [#21]
a
Quote History
Originally Posted By 308223:
Seems like PROOF is using gain twist rifling?  Not a new concept.   The brass case also limits the psi.  Brass flows at a lower temp than steel cases or the thin stainless cases being tried.  Wouldn't  mind one of their Barrels for my ar.
View Quote

Gain-twist traditionally has been moving from something like 1:12 to 1:7 (not actual numbers, just ballparking for reference). PXT is going from like 1:XXX such that it arrives at 1:X at the muzzle. I do think that is very new, though I could be mistaken*. A curve that gradual is very different from previous gain-twists.

I have often heard people say that Proof barrels are expensive for being "just" a reliably accurate barrel. I have not heard anyone claim that Proof sells snake oil. For that reason alone, I am genuinely curious to see how these perform and I expect to see meaningful benefit with all the statements that they and their surrogates are making.

ETA: *To clarify, I mean in normal production volumes. I do not doubt that this may have been something that has been done in the past. Maybe I'm too young, but I cannot recall progressive/exponential twist being mass-marketed like they are doing here.
5/21/2026 5:09:27 PM EDT
[#22]
Easy button here is KS3 uppers and CRS-3 suppressors on current Colt/FN lowers, but the government won’t do that.
5/21/2026 7:05:40 PM EDT
[#23]
Quote History
Originally Posted By medieval_flail:

Carrying around a huge musket is impractical. Even this HICAR thing is sort of silly when you look at modern near peer war in Ukraine where small arms account for only 14% of casualties.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By medieval_flail:
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.

Carrying around a huge musket is impractical. Even this HICAR thing is sort of silly when you look at modern near peer war in Ukraine where small arms account for only 14% of casualties.


When you add a suppressor to a 14.5" carbine its only 3" shorter and weighs the same as a m16a4.

Yeah we're talking about an 11.5 which will give you 6"(with suppressor)and is significant. But then you get to deal with a less reliable system pounding away with 82k PSI.
Do Good
Be Dangerous
Live Free
5/21/2026 7:14:34 PM EDT
[#24]
So 5.56 +P?
Not fly enough to be halal....
5/21/2026 7:16:28 PM EDT
[#25]
In this thread we’re arguing convenient size vs power. I thought this argument was settled when the M14 was retired. I guess not.

If suppressor use isn’t part of the equation, a M16A4 with a collapsible stock might be a decent compromise.
5/21/2026 7:53:46 PM EDT
[Last Edit: 03RN][Edited] [#26]
Originally Posted By 03RN:


When you add a suppressor to a 14.5" carbine its only 3" shorter and weighs the same as a m16a4.

Yeah we're talking about an 11.5 which will give you 6"(with suppressor)and is significant. But then you get to deal with a less reliable system pounding away with 82k PSI.
View Quote

Originally Posted By CheemsK1500:
In this thread we’re arguing convenient size vs power. I thought this argument was settled when the M14 was retired. I guess not.

If suppressor use isn’t part of the equation, a M16A4 with a collapsible stock might be a decent compromise.
View Quote


Also fwiw I dont think we should switch anything. Keep the m4a1s and HKs we have now.

My point of bringing g up m16a4s is due to the desire to increase the power.

14.5s and 16s are good enough. I dont think you're gaining anything to important by speeding it up and factoring the trade offs
Do Good
Be Dangerous
Live Free
5/21/2026 8:13:22 PM EDT
[#27]
Quote History
Originally Posted By panthermark:

It is all basically better new fangled space age materials.  But yeah, when something goes tits up, it could get ugly.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By panthermark:
Originally Posted By CheemsK1500:
I have a feeling a lot of bolt lugs are about to be sacrificed.

It is all basically better new fangled space age materials.  But yeah, when something goes tits up, it could get ugly.

What happens when some of that ammo makes it's way into a standard M4 somewhere, or some allied military firearm.

Just change to a different cartridge.
This is...a clue - Pat_Rogers
I'm not adequately aluminumized for this thread. - gonzo_beyondo
CO, MI, OR - Please lobby your legislators to end discrimination against non-resident CCW permit holders
5/21/2026 8:30:37 PM EDT
[#28]
Quote History
Originally Posted By FedDC:
We can't run the M-4 to its basic capabilities.  The average soldier, LEO, Marine, can't run the legacy rifle anywhere close to what it can do with a simple ACOG.  


We don't even pretend to train to that level or hold a standard approaching it.  


But, yeah...we should buy magic rifles.  


View Quote


Excellent point.
5/21/2026 9:56:13 PM EDT
[#29]
Quote History
Originally Posted By FedDC:
We can't run the M-4 to its basic capabilities.  The average soldier, LEO, Marine, can't run the legacy rifle anywhere close to what it can do with a simple ACOG.  


We don't even pretend to train to that level or hold a standard approaching it.  


But, yeah...we should buy magic rifles.  


View Quote


This is a misconception about high pressure ammunition. It's not magic. Faster bullets shoot flatter. Joe doesn't need to know his holds if we're shooting +/- 1 mil out to 300 yards. Pair that with an optic that does the thinking for you, and you can take a relatively unskilled shooter and have them hitting a reduced c zone out to 800 yards.
5/21/2026 10:56:22 PM EDT
[#30]
Quote History
Originally Posted By cttb:


Excellent point.
View Quote


No it’s not. It lacks basic understanding of the organization.
5/22/2026 1:10:57 AM EDT
[#31]
Quote History
Originally Posted By Gamma762:


What happens when some of that ammo makes it's way into a standard M4 somewhere, or some allied military firearm.

Just change to a different cartridge.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By Gamma762:
Originally Posted By panthermark:
Originally Posted By CheemsK1500:  I have a feeling a lot of bolt lugs are about to be sacrificed.


It is all basically better new fangled space age materials.  But yeah, when something goes tits up, it could get ugly.


What happens when some of that ammo makes it's way into a standard M4 somewhere, or some allied military firearm.

Just change to a different cartridge.


It starts beating itself to death, resulting in a shed lug, possibly a cracked lower.

A case failure would be a little bit more exciting than normal.  Didn't we already hike the pressure on M855A1 over M855?
I sell firearms produced by the finest child labor in the world, be it Filipino, Muslim, Mormon, Arizonan, or Texan.
5/22/2026 2:39:56 AM EDT
[#32]
Quote History
Originally Posted By BrandonP:


This is a misconception about high pressure ammunition. It's not magic. Faster bullets shoot flatter. Joe doesn't need to know his holds if we're shooting +/- 1 mil out to 300 yards. Pair that with an optic that does the thinking for you, and you can take a relatively unskilled shooter and have them hitting a reduced c zone out to 800 yards.
View Quote

Complicates armor too? More lethal lead delivery? Good through barriers?
5/22/2026 4:44:10 AM EDT
[Last Edit: TMS4311][Edited] [#33]
Quote History
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By spydercomonkey:
Originally Posted By 03RN:
Ill just stick with a 20" rifle


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.


I’m betting the ammo solution won’t be Sig.  The Federal Peak Alloy stuff has seen limited testing in LE circles and much more on the military side.  64 gr TBBC is doing 3150 - 3200 fps from 11.5” guns, 70 gr TSX is hovering around 3,000 fps from 11.5” guns.  These are at modest pressures, the cases can safely go much higher.  Faster burning powder with a lower charge weight, steel case that behaves like brass in how it hugs the chamber wall.  Federal really did their homework with this stuff.
5/22/2026 6:16:18 AM EDT
[#34]
Quote History
Originally Posted By GlockPride:


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By GlockPride:
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.


While true, diminishing returns is the biggest hurdle. 855A1 out of an 10.3" or 11.5" barrel is still effective out to 350~400 meters, exactly the effective range of well trained infantry. Bumping up to a 12.5" would get you nearly half of the benefits of higher pressure ammo without the added expense, and what's more, you could set that up with an underslung 40mm, making it a more versatile weapon.

Different tools for different jobs still applies. If you're jumping in and out of trucks, clearing rooms and trenches, 12.5" or shorter is sufficient, and you can still push that out further with modern optics.

If they really want to improve the effectiveness of small units, ultralight LMG, mortar systems, and improved 40mm ammo/launchers would be a better investment.
5/22/2026 6:48:13 AM EDT
[#35]
Quote History
Originally Posted By rb889:


While true, diminishing returns is the biggest hurdle. 855A1 out of an 10.3" or 11.5" barrel is still effective out to 350~400 meters, exactly the effective range of well trained infantry. Bumping up to a 12.5" would get you nearly half of the benefits of higher pressure ammo without the added expense, and what's more, you could set that up with an underslung 40mm, making it a more versatile weapon.

Different tools for different jobs still applies. If you're jumping in and out of trucks, clearing rooms and trenches, 12.5" or shorter is sufficient, and you can still push that out further with modern optics.

If they really want to improve the effectiveness of small units, ultralight LMG, mortar systems, and improved 40mm ammo/launchers would be a better investment.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By rb889:
Originally Posted By GlockPride:
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.


While true, diminishing returns is the biggest hurdle. 855A1 out of an 10.3" or 11.5" barrel is still effective out to 350~400 meters, exactly the effective range of well trained infantry. Bumping up to a 12.5" would get you nearly half of the benefits of higher pressure ammo without the added expense, and what's more, you could set that up with an underslung 40mm, making it a more versatile weapon.

Different tools for different jobs still applies. If you're jumping in and out of trucks, clearing rooms and trenches, 12.5" or shorter is sufficient, and you can still push that out further with modern optics.

If they really want to improve the effectiveness of small units, ultralight LMG, mortar systems, and improved 40mm ammo/launchers would be a better investment.


We're a nation of riflemen.  Magic bullets, dammit!
I sell firearms produced by the finest child labor in the world, be it Filipino, Muslim, Mormon, Arizonan, or Texan.
5/22/2026 7:27:41 AM EDT
[#36]
Quote History
Originally Posted By methical20:
Easy button here is KS3 uppers and CRS-3 suppressors on current Colt/FN lowers, but the government won’t do that.
View Quote

5/22/2026 8:15:47 AM EDT
[#37]
Quote History
Originally Posted By bfoosh06:
I will be looking forward the results of both of these developments.

My hopes are high considering Proof Research has done a lot of the barrel work already.

FYI... a long but great video explaining Proof's work on the barrel.

https://www.youtube.com/watch?v=lF47B1otpvM
View Quote


That was a superb video.

The high pressure 6mm ARC from the Surefire ICAR sounds wild, could explain why SOCOM is going with a short barrel 5.56 here, since if they need more power they can run the 6mm 108gr @ 3100fps?
5/22/2026 8:27:34 AM EDT
[#38]
Quote History
Originally Posted By GlockPride:


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By GlockPride:
Originally Posted By spydercomonkey:


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.


Shorter is easier when clearing buildings, getting in and out of vehicles and not as long when suppressed.


Yes, but they are essentially using High Pressure Cases + Advanced barrel tech + Advanced bolt tech, to replicate the 31" weapon w/ M16 ballistics the Stery AUG offered in 1977.



Whereas if the High Pressure was fired from a 16"-20" and hitting 3400-3500fps, thats genuinely new ballistic territory, akin to a .22-250, and might actually be able to punch through some Level IV with Tungsten, or III+ with the steel core M855A1.

With the new MFMD suppressor design, increase in barrel length over unsuppressed is only like 1", which could allow more 'barrel budget'.


5/22/2026 8:30:14 AM EDT
[#39]
Quote History
Originally Posted By TMS4311:


I’m betting the ammo solution won’t be Sig.  The Federal Peak Alloy stuff has seen limited testing in LE circles and much more on the military side.  64 gr TBBC is doing 3150 - 3200 fps from 11.5” guns, 70 gr TSX is hovering around 3,000 fps from 11.5” guns.  These are at modest pressures, the cases can safely go much higher.  Faster burning powder with a lower charge weight, steel case that behaves like brass in how it hugs the chamber wall.  Federal really did their homework with this stuff.
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Originally Posted By TMS4311:
Originally Posted By spydercomonkey:
Originally Posted By 03RN:
Ill just stick with a 20" rifle


Honestly a fair comparison, and points to a flaw / missed opportunity with the HICAR.

M855A1
11.5" ~ 2750fps
20" ~ 3100fps

We don't know what the official velocity of the new "M855A1+" would be, but SIG claimed +400fps for its load with SSD (that seems a bit high to me):

https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/

-->M855A1+ 11.5" ~ 3150fps

That's something to be sure, but less exciting then the ~3400fps potential of a 16", or 3500fps potential from a 20".

IMO seems like a waste going with such a short barrel.


I’m betting the ammo solution won’t be Sig.  The Federal Peak Alloy stuff has seen limited testing in LE circles and much more on the military side.  64 gr TBBC is doing 3150 - 3200 fps from 11.5” guns, 70 gr TSX is hovering around 3,000 fps from 11.5” guns.  These are at modest pressures, the cases can safely go much higher.  Faster burning powder with a lower charge weight, steel case that behaves like brass in how it hugs the chamber wall.  Federal really did their homework with this stuff.


Wonderful info, thank you.

That's excellent performance, and is in line with the +400fps SIG claimed, in what sounds like a better case. And I just instinctively trust Federal much more as an ammo OEM then SIG.
5/22/2026 9:29:22 AM EDT
[#40]
Quote History
Originally Posted By spydercomonkey:


Yes, but they are essentially using High Pressure Cases + Advanced barrel tech + Advanced bolt tech, to replicate the 31" weapon w/ M16 ballistics the Stery AUG offered in 1977.

https://uploads.tapatalk-cdn.com/20160224/18f780e6cbaa469ced347b61c2b9fd77.jpg

Whereas if the High Pressure was fired from a 16"-20" and hitting 3400-3500fps, thats genuinely new ballistic territory, akin to a .22-250, and might actually be able to punch through some Level IV with Tungsten, or III+ with the steel core M855A1.

With the new MFMD suppressor design, increase in barrel length over unsuppressed is only like 1", which could allow more 'barrel budget'.

https://strategicsciences.us/assets/mfmd/weapon-systems/5-56-urg-i-14-5-md-1-3-side-fe442d88.webp
View Quote

The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.
5/22/2026 10:04:33 AM EDT
[#41]
Quote History
Originally Posted By spydercomonkey:


Yes, but they are essentially using High Pressure Cases + Advanced barrel tech + Advanced bolt tech, to replicate the 31" weapon w/ M16 ballistics the Stery AUG offered in 1977.

https://uploads.tapatalk-cdn.com/20160224/18f780e6cbaa469ced347b61c2b9fd77.jpg

Whereas if the High Pressure was fired from a 16"-20" and hitting 3400-3500fps, thats genuinely new ballistic territory, akin to a .22-250, and might actually be able to punch through some Level IV with Tungsten, or III+ with the steel core M855A1.

With the new MFMD suppressor design, increase in barrel length over unsuppressed is only like 1", which could allow more 'barrel budget'.

https://strategicsciences.us/assets/mfmd/weapon-systems/5-56-urg-i-14-5-md-1-3-side-fe442d88.webp
View Quote

But bullpups bad.
5/22/2026 10:08:42 AM EDT
[#42]
Quote History
Originally Posted By PacificNic:

The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.
View Quote

I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.
5/22/2026 10:19:49 AM EDT
[#43]
Quote History
Originally Posted By medieval_flail:


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.
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Originally Posted By medieval_flail:
Originally Posted By PacificNic:  The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.


Anything supersonic isn't hearing safe.
I sell firearms produced by the finest child labor in the world, be it Filipino, Muslim, Mormon, Arizonan, or Texan.
5/22/2026 10:57:13 AM EDT
[#44]
Quote History
Originally Posted By backbencher:


Anything supersonic isn't hearing safe.
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Originally Posted By backbencher:
Originally Posted By medieval_flail:
Originally Posted By PacificNic:  The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.


Anything supersonic isn't hearing safe.


Yeah but it can be pretty close. Do people use ear pro when shooting .22s?
Do Good
Be Dangerous
Live Free
5/22/2026 11:36:26 AM EDT
[#45]
Quote History
Originally Posted By 03RN:


Yeah but it can be pretty close. Do people use ear pro when shooting .22s?
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Originally Posted By 03RN:
Originally Posted By backbencher:
Originally Posted By medieval_flail:
Originally Posted By PacificNic:  The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.


Anything supersonic isn't hearing safe.


Yeah but it can be pretty close. Do people use ear pro when shooting .22s?


I double bag when I shoot anything at a range.  I might only be shooting subsonic .22 through a can, but the guy next to me is firing his supersonic .300 Blackout through a 7.5" barrel w/ an ObnoxiousTM brake.
I sell firearms produced by the finest child labor in the world, be it Filipino, Muslim, Mormon, Arizonan, or Texan.
5/22/2026 11:39:43 AM EDT
[#46]
Quote History
Originally Posted By BrandonP:


This is a misconception about high pressure ammunition. It's not magic. Faster bullets shoot flatter. Joe doesn't need to know his holds if we're shooting +/- 1 mil out to 300 yards. Pair that with an optic that does the thinking for you, and you can take a relatively unskilled shooter and have them hitting a reduced c zone out to 800 yards.
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Originally Posted By BrandonP:
Originally Posted By FedDC:
We can't run the M-4 to its basic capabilities.  The average soldier, LEO, Marine, can't run the legacy rifle anywhere close to what it can do with a simple ACOG.  


We don't even pretend to train to that level or hold a standard approaching it.  


But, yeah...we should buy magic rifles.  




This is a misconception about high pressure ammunition. It's not magic. Faster bullets shoot flatter. Joe doesn't need to know his holds if we're shooting +/- 1 mil out to 300 yards. Pair that with an optic that does the thinking for you, and you can take a relatively unskilled shooter and have them hitting a reduced c zone out to 800 yards.



They can't do any of that because they don't understand the basics of gunfighting.  It's not the tool...it is the user.  Nobody is missing because they don't know their hold, just like they don't understand how much a mil is or what the magic lines in the optic mean.  


They can't gunfight.  More expensive rifles and optics with batteries won't fix that.  It has to be built and nobody wants to build it outside SOCOM and a few Infantry units.  


Their rifles don't run.  Their optics aren't zero'd.  Their lasers are a disaster with completely incorrect settings and switches.  Their slings and white lights are a mess.  Their mags are dented and broken.  Their kit is set up to prevent any semblance of effective use of a rifle or pistol...


This isn't a new problem.  It was this way in early GWOT.  It is back to it now.  Casualties are the only thing that fixes it.
5/22/2026 11:51:48 AM EDT
[#47]
Quote History
Originally Posted By FedDC:



They can't do any of that because they don't understand the basics of gunfighting.  It's not the tool...it is the user.  Nobody is missing because they don't know their hold, just like they don't understand how much a mil is or what the magic lines in the optic mean.  


They can't gunfight.  More expensive rifles and optics with batteries won't fix that.  It has to be built and nobody wants to build it outside SOCOM and a few Infantry units.  


Their rifles don't run.  Their optics aren't zero'd.  Their lasers are a disaster with completely incorrect settings and switches.  Their slings and white lights are a mess.  Their mags are dented and broken.  Their kit is set up to prevent any semblance of effective use of a rifle or pistol...


This isn't a new problem.  It was this way in early GWOT.  It is back to it now.  Casualties are the only thing that fixes it.
View Quote

The first paragraph seems to contradict the ones that follow. If one knows how to shoot and is proficient with ranging and holdovers why would they allow their issued weapon to be in such a sorry state? (Other than months in a foxhole without relief that is).
5/22/2026 12:31:28 PM EDT
[#48]
Quote History
Originally Posted By backbencher:


I double bag when I shoot anything at a range.  I might only be shooting subsonic .22 through a can, but the guy next to me is firing his supersonic .300 Blackout through a 7.5" barrel w/ an ObnoxiousTM brake.
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Originally Posted By backbencher:
Originally Posted By 03RN:
Originally Posted By backbencher:
Originally Posted By medieval_flail:
Originally Posted By PacificNic:  The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.


Anything supersonic isn't hearing safe.


Yeah but it can be pretty close. Do people use ear pro when shooting .22s?


I double bag when I shoot anything at a range.  I might only be shooting subsonic .22 through a can, but the guy next to me is firing his supersonic .300 Blackout through a 7.5" barrel w/ an ObnoxiousTM brake.

Understandable but if you were not shooting around others and were only shooting a 22 would you wear any?
Do Good
Be Dangerous
Live Free
5/22/2026 12:59:19 PM EDT
[#49]
Quote History
Originally Posted By 03RN:

Understandable but if you were not shooting around others and were only shooting a 22 would you wear any?
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Honestly, probably not. I will never intentionally expose myself to 5.56mm with bare ears if I can avoid it. You can be pedantic if you'd like, but no one who cares about you is going to tell you that 5.56mm is hearing-safe with their suppressor.
5/22/2026 12:59:31 PM EDT
[#50]
Quote History
Originally Posted By 03RN:


Understandable but if you were not shooting around others and were only shooting a 22 would you wear any?
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Quote History
Originally Posted By 03RN:
Originally Posted By backbencher:
Originally Posted By 03RN:
Originally Posted By backbencher:
Originally Posted By medieval_flail:
Originally Posted By PacificNic:  The moment that they tried to sell me on the MFMD being "hearing-safe" on a 5.56mm platform, I stopped listening to any of the marketing slop about this. It might genuinely be a great piece of hardware, but I cannot stand gimmicky tactics.


I require Pew Science data for an objective assessment, as with any can, however the doubled up ridiculous MFMD that I heard in person was pretty quiet even under covered shooting.


Anything supersonic isn't hearing safe.


Yeah but it can be pretty close. Do people use ear pro when shooting .22s?


I double bag when I shoot anything at a range.  I might only be shooting subsonic .22 through a can, but the guy next to me is firing his supersonic .300 Blackout through a 7.5" barrel w/ an ObnoxiousTM brake.


Understandable but if you were not shooting around others and were only shooting a 22 would you wear any?


If I'm not shooting subsonics suppressed, absolutely.  I have all the Reeeeee I want, am already getting the check, .gov isn't going to pay me more if it's louder.
I sell firearms produced by the finest child labor in the world, be it Filipino, Muslim, Mormon, Arizonan, or Texan.

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