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 New BCM RECCE 14.5 short stroking
chivvalry  [Member]
1/9/2012 1:37:26 PM
Finally got to the range to sight in my new Bravo Company RECCE 14.5 middy and the damn thing is short stroking on Wolf ammo. It cycles the Federal xm193 and Remington .223 stuff just fine but turns into a single shot with the Wolf ammo. Several times it jammed with a round diagonal in the chamber...

I am extremely dissappointed right now... I have an email in to BCM asking what I, or better yet they, can do about this. I'm guessing the gas block is misaligned or a burr in either the barrel gas hole or something else not allowing a good gas flow.

.
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Bklyn_Irish  [Team Member]
1/9/2012 1:40:45 PM
Originally Posted By chivvalry:
Finally got to the range to sight in my new Bravo Company RECCE 14.5 middy and the damn thing is short stroking on Wolf ammo. It cycles the Federal xm193 and Remington .223 stuff just fine but turns into a single shot with the Wolf ammo. Several times it jammed with a round diagonal in the chamber...

I am extremely dissappointed right now... I have an email in to BCM asking what I, or better yet they, can do about this. I'm guessing the gas block is misaligned or a burr in either the barrel gas hole or something else not allowing a good gas flow.

.


...or the Wolf is too weak for a 14.5" midlength gas system.
AR15fan  [Team Member]
1/9/2012 1:45:13 PM
What you are likely to hear is BCM is optimized for 5.56mm ammo and that .223 ammo might not work.


Have you tried it with a standard Carbine Buffer and milspec buffer spring?

Middies do not need H, H2, T2, H3, 9mm, ext heavy buffers.

chivvalry  [Member]
1/9/2012 1:48:33 PM
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:
Finally got to the range to sight in my new Bravo Company RECCE 14.5 middy and the damn thing is short stroking on Wolf ammo. It cycles the Federal xm193 and Remington .223 stuff just fine but turns into a single shot with the Wolf ammo. Several times it jammed with a round diagonal in the chamber...

I am extremely dissappointed right now... I have an email in to BCM asking what I, or better yet they, can do about this. I'm guessing the gas block is misaligned or a burr in either the barrel gas hole or something else not allowing a good gas flow.

.


...or the Wolf is too weak for a 14.5" midlength gas system.


I certainly hope that's not the answer. I know the Wolf and other cheap steel jacketed rounds aren't the most robust but they cycle just fine in my colt with a 20 inch barrel and full rifle length system. The pressures would likely be even lower in that system wouldn't they?
chivvalry  [Member]
1/9/2012 1:51:50 PM
Originally Posted By AR15fan:
What you are likely to hear is BCM is optimized for 5.56mm ammo and that .223 ammo might not work.


Have you tried it with a standard Carbine Buffer and milspec buffer spring?

Middies do not need H, H2, T2, H3, 9mm, ext heavy buffers.



I have not. I don't have spare parts to swap in and out. At this point I intend to do nothing until I hear from BCM since anything I do will necessitate purchasing parts and or tearing into the gun. I don't want to start fiddling with it and have them say they won't touch it since I messed with it.
BSWilson  [Member]
1/9/2012 1:52:17 PM
Newsflash:

14.5" middies lack enough barrel ahead of the gas port for reliable function, when compared to the carbine position.
Bklyn_Irish  [Team Member]
1/9/2012 2:15:56 PM
Originally Posted By BSWilson:
Newsflash:

14.5" middies lack enough barrel ahead of the gas port for reliable function, when compared to the carbine position.


Don't tell her that. She runs like a raped ape suppressed and unsuppressed.



Lower:
Complete Spike's Lower, once part of a Spike's M4LE (Spike's Tactical)
Spike's ST-T2 Buffer
Ergo Grip (Brownells)
Magpul B.A.D. Lever (Brownells)
Blue Force Gear VCAS (Brownells)
M.I. Rear Sling Mount

Upper:
Spike's Tactical upper (once part of a Spike's 10.5" upper from AIM Surplus)
14.5" Daniel Defense Lightweight Midlength Barrel (PK Firearms, mounted by ADCO)
SEI/Gemtech G5 Vortex suppressor mount (Gemtech, mounted by ADCO)
13" Troy TRX Extreme rail (Troy, mounted by ADCO)
Nikon M223 1-4x (Bud's Gun Shop)
LaRue Tactical Mount (LaRue)
Surefire Scout (EE) in Gear Sector Offset Mount (Gear Sector)
Troy Front & Rear Battlesight (Troy)
Magpul AFG (Brownells)
chivvalry  [Member]
1/9/2012 2:21:00 PM
Originally Posted By BSWilson:
Newsflash:

14.5" middies lack enough barrel ahead of the gas port for reliable function, when compared to the carbine position.


I don't buy that the .05 ms difference in dwell time between a middy on a 14.5 and a middy on a 16 would make that much difference... Especially when my colt 20" and rifle system will cycle the same Wolf ammo at lower pressures.
KILLERB6  [Team Member]
1/9/2012 2:38:05 PM
Originally Posted By chivvalry:
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:
Finally got to the range to sight in my new Bravo Company RECCE 14.5 middy and the damn thing is short stroking on Wolf ammo. It cycles the Federal xm193 and Remington .223 stuff just fine but turns into a single shot with the Wolf ammo. Several times it jammed with a round diagonal in the chamber...

I am extremely dissappointed right now... I have an email in to BCM asking what I, or better yet they, can do about this. I'm guessing the gas block is misaligned or a burr in either the barrel gas hole or something else not allowing a good gas flow.

.


...or the Wolf is too weak for a 14.5" midlength gas system.


I certainly hope that's not the answer. I know the Wolf and other cheap steel jacketed rounds aren't the most robust but they cycle just fine in my colt with a 20 inch barrel and full rifle length system. The pressures would likely be even lower in that system wouldn't they?


But that's the answer.

A lighter buffer may enable it to run on lower powered ammo.
Dano523  [Moderator]
1/9/2012 2:38:46 PM
Originally Posted By AR15fan:
What you are likely to hear is BCM is optimized for 5.56mm ammo and that .223 ammo might not work.


Have you tried it with a standard Carbine Buffer and milspec buffer spring?

Middies do not need H, H2, T2, H3, 9mm, ext heavy buffers.




Yep, Nato ammo is hotter than 223 ammo, and with the wolf steel poly coated cases and new chamber, might have a problem is you are running a H or heaver buffer than just a standard Carbine 2.9 oz buffer.

Also, little trick with the wolf ammo, run the upper bearing surfaces on the CLP wetter side for that ammo.
chivvalry  [Member]
1/9/2012 3:07:47 PM
Originally Posted By Dano523:
Originally Posted By AR15fan:
What you are likely to hear is BCM is optimized for 5.56mm ammo and that .223 ammo might not work.


Have you tried it with a standard Carbine Buffer and milspec buffer spring?

Middies do not need H, H2, T2, H3, 9mm, ext heavy buffers.




Yep, Nato ammo is hotter than 223 ammo, and with the wolf steel poly coated cases and new chamber, might have a problem is you are running a H or heaver buffer than just a standard Carbine 2.9 oz buffer.

Also, little trick with the wolf ammo, run the upper bearing surfaces on the CLP wetter side for that ammo.


It's running an H buffer which is 3.9 oz, I think? If BCM doesn't help me out that might be the first fix attempt then? Swapping out to a carbine buffer I mean...
Bklyn_Irish  [Team Member]
1/9/2012 3:15:12 PM
Originally Posted By chivvalry:
Originally Posted By Dano523:
Originally Posted By AR15fan:
What you are likely to hear is BCM is optimized for 5.56mm ammo and that .223 ammo might not work.


Have you tried it with a standard Carbine Buffer and milspec buffer spring?

Middies do not need H, H2, T2, H3, 9mm, ext heavy buffers.




Yep, Nato ammo is hotter than 223 ammo, and with the wolf steel poly coated cases and new chamber, might have a problem is you are running a H or heaver buffer than just a standard Carbine 2.9 oz buffer.

Also, little trick with the wolf ammo, run the upper bearing surfaces on the CLP wetter side for that ammo.


It's running an H buffer which is 3.9 oz, I think? If BCM doesn't help me out that might be the first fix attempt then? Swapping out to a carbine buffer I mean...


That would be my recommendation.

chivvalry  [Member]
1/9/2012 3:55:30 PM
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:

It's running an H buffer which is 3.9 oz, I think? If BCM doesn't help me out that might be the first fix attempt then? Swapping out to a carbine buffer I mean...


That would be my recommendation.



okay, thanks guys... That was at least two votes for trying the carbine buffer so I will give that a shot if BCM doesn't fix me up.
lane5000  [Member]
1/9/2012 3:58:17 PM
Originally Posted By chivvalry:
Finally got to the range to sight in my new Bravo Company RECCE 14.5 middy and the damn thing is short stroking on Wolf ammo. It cycles the Federal xm193 and Remington .223 stuff just fine but turns into a single shot with the Wolf ammo. Several times it jammed with a round diagonal in the chamber...

I am extremely dissappointed right now... I have an email in to BCM asking what I, or better yet they, can do about this. I'm guessing the gas block is misaligned or a burr in either the barrel gas hole or something else not allowing a good gas flow.

.


And you would be so, so wrong. Wolf is notoriously weak ammo so it likely doesn't have the "oomph" to fully cycle the action. Definitely not the rifle's fault when you feed it garbage.
Bklyn_Irish  [Team Member]
1/9/2012 4:02:39 PM
Originally Posted By chivvalry:
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:

It's running an H buffer which is 3.9 oz, I think? If BCM doesn't help me out that might be the first fix attempt then? Swapping out to a carbine buffer I mean...


That would be my recommendation.



okay, thanks guys... That was at least two votes for trying the carbine buffer so I will give that a shot if BCM doesn't fix me up.



How do you expect BCM to "fix you up?"
chivvalry  [Member]
1/9/2012 4:20:48 PM
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:
Originally Posted By Bklyn_Irish:
Originally Posted By chivvalry:

It's running an H buffer which is 3.9 oz, I think? If BCM doesn't help me out that might be the first fix attempt then? Swapping out to a carbine buffer I mean...


That would be my recommendation.



okay, thanks guys... That was at least two votes for trying the carbine buffer so I will give that a shot if BCM doesn't fix me up.



How do you expect BCM to "fix you up?"


Tell me I'm an idiot for using shitty ammo? Say, yep, we've seen that with that config and there was nothing wrong with the gas system but we had the guy do "x" and it cleared it up? Say, nope, it should cycle even with that, send it back to us and we will check it over?

It's their design, I want to know if wolf not cycling is expected and normal (in which case how do I mod it so it will cycle) or if it unexpected and not normal. Hell I don't know exactly... What I do know is I feel I have a problem and I would like them to confirm or deny that.

.


Saddlerocker  [Member]
1/9/2012 4:32:18 PM
There is a warning on BCM website on the 14.5" Mid-lengths that says to use full power 5.56 ammo, because they are optimized for 5.56 pressure. And if using lower power ammo they recommend using a Carbine buffer.

EDIT: Link to BCM website. The info about low pressure ammo is right above the words "Professional Grade Weaponry, by BCM"
http://www.bravocompanyusa.com/BCM-14-5-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-14%20ddl12.htm
Heres the Quote from BCM's Website....
"These 14.5" mid length gas barreled upper receiver groups have been specifically tuned to be a very soft and fast shooting set up. They are a joy to shoot, but please feed it good ammo. With good milspec pressured ammo we have been running H buffers. We do not recommend using lower powered ammo. If using less than milspec pressured ammo, it may be best to run a standard carbine buffer."

Lots of people can run it fine with Russian ammo, but some cant. I bet a carbine buffer would allow you to run it fine. A carbine buffer AND some Barnaul WPA or Brown Bear, which is a little hotter than black box wolf, should certainly work.
chivvalry  [Member]
1/9/2012 4:36:21 PM
Originally Posted By Saddlerocker:
There is a warning on BCM website on the 14.5" Mid-lengths that says to use full power 5.56 ammo, because they are optimized for 5.56 pressure. And if using lower power ammo they recommend using a Carbine buffer.

Lots of people can run it fine with Russian ammo, but some cant. I bet a carbine buffer would allow you to run it fine. A carbine buffer AND some Barnaul WPA or Brown Bear should certainly work.


Really? Where's that at? That will probably be their answer if so! LOL

Edit: Just read the full quote you listed, that is definitely the answer then. I would still love the link to that. I guess I need to order a cabine buffer then. Good to know and thanks so much for finding that! It does shoot smooth as butter with the good stuff.

2nd edit.... Saddle rocker... You nailed it. Thanks very very much.
chivvalry  [Member]
1/9/2012 4:49:07 PM
...and I just got an email response from them...

Saying they don't recommend the low power ammo but if you want to use it you will have to replace the buffer with a standard carbine buffer to get it to cycle correctly.

I feel much better now. Thanks again guys.
m_lowlander  [Member]
1/10/2012 3:48:04 PM
Glad you got it figured out.... I believe I was right next to your lane at PMSC when it was choking.
Small world even smaller internets... lol

M
Dano523  [Moderator]
1/10/2012 5:08:46 PM
Originally Posted By Saddlerocker:
There is a warning on BCM website on the 14.5" Mid-lengths that says to use full power 5.56 ammo, because they are optimized for 5.56 pressure. And if using lower power ammo they recommend using a Carbine buffer.

EDIT: Link to BCM website. The info about low pressure ammo is right above the words "Professional Grade Weaponry, by BCM"
http://www.bravocompanyusa.com/BCM-14-5-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-14%20ddl12.htm
Heres the Quote from BCM's Website....
"These 14.5" mid length gas barreled upper receiver groups have been specifically tuned to be a very soft and fast shooting set up. They are a joy to shoot, but please feed it good ammo. With good milspec pressured ammo we have been running H buffers. We do not recommend using lower powered ammo. If using less than milspec pressured ammo, it may be best to run a standard carbine buffer."


OK, besides surplus ammo, point me to where you can buy New Nato spec loaded ammo that BCM refers to use in the rig.

You won't, since the LC ammo being offered to the public is either XM or PD (not mil spec), and when it comes to other brands manufactored for the states, loaded to 223 SAAMI spec's instead (which Wolf ammo is loaded to as well). Nato working pressures, 62K, while 223 sammi is loaded to 55K working pressures in general instead. Further more, depending on the bullet weight, and even powder used, you have venerations at the gas port as well (read a Nato M-193 will have less pressure at the gas port than Sammi match 69gr ammo, since the slower buring powder will have it peak dwell closer to the gas port, and will have more residual pressure at the gas port instead.

Bottom line, if the chamber is mil spec not only in head space, but cross wall demensions (inducing it being reamed to a smooth finish), with the correct gas port and buffer, steel case ammo will not be a problem through the rifle. If the rifle will not run steel case ammo, than all you have to ask yourself is what is different in the above, then say a Colt or FN barrel.

Saddlerocker  [Member]
1/10/2012 9:12:23 PM
Originally Posted By Dano523:
Originally Posted By Saddlerocker:
There is a warning on BCM website on the 14.5" Mid-lengths that says to use full power 5.56 ammo, because they are optimized for 5.56 pressure. And if using lower power ammo they recommend using a Carbine buffer.

EDIT: Link to BCM website. The info about low pressure ammo is right above the words "Professional Grade Weaponry, by BCM"
http://www.bravocompanyusa.com/BCM-14-5-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-14%20ddl12.htm
Heres the Quote from BCM's Website....
"These 14.5" mid length gas barreled upper receiver groups have been specifically tuned to be a very soft and fast shooting set up. They are a joy to shoot, but please feed it good ammo. With good milspec pressured ammo we have been running H buffers. We do not recommend using lower powered ammo. If using less than milspec pressured ammo, it may be best to run a standard carbine buffer."


OK, besides surplus ammo, point me to where you can buy New Nato spec loaded ammo that BCM refers to use in the rig.

You won't, since the LC ammo being offered to the public is either XM or PD (not mil spec), and when it comes to other brands manufactored for the states, loaded to 223 SAAMI spec's instead (which Wolf ammo is loaded to as well). Nato working pressures, 62K, while 223 sammi is loaded to 55K working pressures in general instead. Further more, depending on the bullet weight, and even powder used, you have venerations at the gas port as well (read a Nato M-193 will have less pressure at the gas port than Sammi match 69gr ammo, since the slower buring powder will have it peak dwell closer to the gas port, and will have more residual pressure at the gas port instead.

Bottom line, if the chamber is mil spec not only in head space, but cross wall demensions (inducing it being reamed to a smooth finish), with the correct gas port and buffer, steel case ammo will not be a problem through the rifle. If the rifle will not run steel case ammo, than all you have to ask yourself is what is different in the above, then say a Colt or FN barrel.



I know you know that the 14.5" mid-length can be a fine line with underpowered ammo when coupled with an H bufffer.
That is all it is.
BCM' statement might be a little over the top considering I have never heard of .223 not functioning, but the weakest russian ammo (wolf/Tula) coupled with an H buffer is no surprise.

Your last statement would lead people to believe that no matter the combination of the weakest ammo and heaviest buffer, the gun should function if the chamber and gas port are in spec (which there is no spec for mid-length gas port anyhow), and the gas block/FSB is lined up.
chivvalry  [Member]
1/11/2012 10:05:06 AM
Originally Posted By m_lowlander:
Glad you got it figured out.... I believe I was right next to your lane at PMSC when it was choking.
Small world even smaller internets... lol

M


With the cigar or the two kids? After I left the rifle range I went up to one of the bays and worked it over a bit more. She was eating everything except the Wolf and that other steel case stuff from cabelas just fine. I admit to being a little annoyed the rest of the day and Monday that my pretty new rifle wasnt working as I had expected. I am relieved to find out it is almost certainly because I was feeding a highly tuned rifle crappy ammo and that I have an easy mod to get it to eat said crappy ammo when I desire.
chivvalry  [Member]
1/11/2012 10:12:02 AM
Originally Posted By Dano523:
Originally Posted By Saddlerocker:
There is a warning on BCM website on the 14.5" Mid-lengths that says to use full power 5.56 ammo, because they are optimized for 5.56 pressure. And if using lower power ammo they recommend using a Carbine buffer.

EDIT: Link to BCM website. The info about low pressure ammo is right above the words "Professional Grade Weaponry, by BCM"
http://www.bravocompanyusa.com/BCM-14-5-Mid-Length-Upper-Receiver-Daniel-Defense-p/bcm-urg-mid-14%20ddl12.htm
Heres the Quote from BCM's Website....
"These 14.5" mid length gas barreled upper receiver groups have been specifically tuned to be a very soft and fast shooting set up. They are a joy to shoot, but please feed it good ammo. With good milspec pressured ammo we have been running H buffers. We do not recommend using lower powered ammo. If using less than milspec pressured ammo, it may be best to run a standard carbine buffer."


OK, besides surplus ammo, point me to where you can buy New Nato spec loaded ammo that BCM refers to use in the rig.

You won't, since the LC ammo being offered to the public is either XM or PD (not mil spec), and when it comes to other brands manufactored for the states, loaded to 223 SAAMI spec's instead (which Wolf ammo is loaded to as well). Nato working pressures, 62K, while 223 sammi is loaded to 55K working pressures in general instead. Further more, depending on the bullet weight, and even powder used, you have venerations at the gas port as well (read a Nato M-193 will have less pressure at the gas port than Sammi match 69gr ammo, since the slower buring powder will have it peak dwell closer to the gas port, and will have more residual pressure at the gas port instead.

Bottom line, if the chamber is mil spec not only in head space, but cross wall demensions (inducing it being reamed to a smooth finish), with the correct gas port and buffer, steel case ammo will not be a problem through the rifle. If the rifle will not run steel case ammo, than all you have to ask yourself is what is different in the above, then say a Colt or FN barrel.



They recommended Sierra or Black Hills ammo in their email response to me. And that stuff is a little pricey... Since it was cycling the Remington .223 just fine I don't think it was tuned to ONLY fire 5.56 mil spec ammo. The Federal xm193 also ran smoothly which would be expected of course...

.
chivvalry  [Member]
1/11/2012 12:30:46 PM
So I got a buffer from a guy that said it came from a Bushmaster carbine... When I look at the buffers side by side the Bushmaster has a noticeably smaller diameter than the H buffer I pulled out. Is this a commercial vs.. Mil spec buffer? Should I not use this buffer? The head looks okay, the spring clicks on fine, and the pin holds it in...
m_lowlander  [Member]
1/11/2012 2:35:37 PM
Originally Posted By chivvalry:
Originally Posted By m_lowlander:
Glad you got it figured out.... I believe I was right next to your lane at PMSC when it was choking.
Small world even smaller internets... lol

M


With the cigar or the two kids? After I left the rifle range I went up to one of the bays and worked it over a bit more. She was eating everything except the Wolf and that other steel case stuff from cabelas just fine. I admit to being a little annoyed the rest of the day and Monday that my pretty new rifle wasnt working as I had expected. I am relieved to find out it is almost certainly because I was feeding a highly tuned rifle crappy ammo and that I have an easy mod to get it to eat said crappy ammo when I desire.


The one with the two kids chewing up my ammo. Hope it works for you. I feed my Stag everything and anything and it has yet to fail to eat whatever I shove into it....
M
chivvalry  [Member]
1/11/2012 4:21:23 PM
Originally Posted By m_lowlander:
Originally Posted By chivvalry:
Originally Posted By m_lowlander:
Glad you got it figured out.... I believe I was right next to your lane at PMSC when it was choking.
Small world even smaller internets... lol

M


With the cigar or the two kids? After I left the rifle range I went up to one of the bays and worked it over a bit more. She was eating everything except the Wolf and that other steel case stuff from cabelas just fine. I admit to being a little annoyed the rest of the day and Monday that my pretty new rifle wasnt working as I had expected. I am relieved to find out it is almost certainly because I was feeding a highly tuned rifle crappy ammo and that I have an easy mod to get it to eat said crappy ammo when I desire.


The one with the two kids chewing up my ammo. Hope it works for you. I feed my Stag everything and anything and it has yet to fail to eat whatever I shove into it....
M


Heh, yeah they were! I'm somewhat confident the lighter buffer will resolve the problem, which is great because swapping the buffer when I want to run quality ammo as soft as possible and then cheap crap for target practice will be easy.
chivvalry  [Member]
1/18/2012 4:53:12 PM
For anyone that is interested, the carbine buffer solved it just fine! She's running the wolf ammo within. The difference between the recoil feel with the carbine buffer and good ammo and the h buffer and good ammo is actually more than I expected... So, since the buffer swap is so easy I will keep both buffers available for range work and keep the h buffer in the gun with good ammo for when it is hanging around the house.

Thanks for all the responses and help!

iNeXile556  [Team Member]
1/18/2012 9:07:20 PM

Originally Posted By chivvalry:

I don't buy that the .05 ms difference in dwell time between a middy on a 14.5 and a middy on a 16 would make that much difference... Especially when my colt 20" and rifle system will cycle the same Wolf ammo at lower pressures.

There's a 23.2% increase in dwell time in the 16" over the 14.5. There is however a 32.5% decrease in dwell time when you go from a 14.5 carbine to a 14.5 middy.

The 14.5 in a carbine length is the closest set up to the "perfect" dwell time, but there is a 13% pressure increase over the middy.
Bottom line, in a situation where a failure may get you dead, I'll take the 14.5 carbine.


ETA: Your 20" rifle has the same dwell time as the 16" middy.
Dano523  [Moderator]
1/19/2012 10:08:31 AM
Originally Posted By iNeXile556:

Originally Posted By chivvalry:

I don't buy that the .05 ms difference in dwell time between a middy on a 14.5 and a middy on a 16 would make that much difference... Especially when my colt 20" and rifle system will cycle the same Wolf ammo at lower pressures.

There's a 23.2% increase in dwell time in the 16" over the 14.5. There is however a 32.5% decrease in dwell time when you go from a 14.5 carbine to a 14.5 middy.

The 14.5 in a carbine length is the closest set up to the "perfect" dwell time, but there is a 13% pressure increase over the middy.
Bottom line, in a situation where a failure may get you dead, I'll take the 14.5 carbine.


ETA: Your 20" rifle has the same dwell time as the 16" middy.



Yes, no, maybe.

Got to remember that all your figure are at the bore side of the gas port. The size of the gas port will determine the amount of dwell time/ pressure that the B/C sees, so you would have to supply gas port sizes for all of the above to actual determine what the B/C is seeing in pressures/dwell times for your differences stated above. Think of it as doing the match between the original Garand gas trap system, to the gas cylinder system that replacement it.
iNeXile556  [Team Member]
1/19/2012 9:14:30 PM

Originally Posted By Dano523:
Originally Posted By iNeXile556:

Originally Posted By chivvalry:

I don't buy that the .05 ms difference in dwell time between a middy on a 14.5 and a middy on a 16 would make that much difference... Especially when my colt 20" and rifle system will cycle the same Wolf ammo at lower pressures.

There's a 23.2% increase in dwell time in the 16" over the 14.5. There is however a 32.5% decrease in dwell time when you go from a 14.5 carbine to a 14.5 middy.

The 14.5 in a carbine length is the closest set up to the "perfect" dwell time, but there is a 13% pressure increase over the middy.
Bottom line, in a situation where a failure may get you dead, I'll take the 14.5 carbine.


ETA: Your 20" rifle has the same dwell time as the 16" middy.



Yes, no, maybe.

Got to remember that all your figure are at the bore side of the gas port. The size of the gas port will determine the amount of dwell time/ pressure that the B/C sees, so you would have to supply gas port sizes for all of the above to actual determine what the B/C is seeing in pressures/dwell times for your differences stated above. Think of it as doing the match between the original Garand gas trap system, to the gas cylinder system that replacement it.
Well, kinda.

Dwell time is the amount of time the gas system is pressurized and available, it does not have anything to do with port size or pressure in any measurable amount. The system is only pressurized from the time the projectile passes the gas port until it exits the muzzle. This is the dwell time. You could argue that a higher pressure will reach the carrier faster and thereby increase dwell time, but we are only talking microseconds. The same argument could be made that a faster velocity of the projectile will decrease dwell time, again we are in the realm of microseconds. Any significant change to dwell time can only be obtained by changing the the gas port to muzzle distance. Of course devices like suppressors do have an effect on dwell time by lengthening the time the pressure is available to the gas system due to the trapped expanding gas in the baffles which creates back pressure, effectively "lengthening" the barrel.

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