Rem 700 maxchamber pressure

[roostercogburn98]

I recently got an email from a gentleman who says a certain round that was designed for a delayed blowback style gun would cause excess chamber pressure in a bolt action rifle. He said in the range of 127,000 PSI. This sounds a but silly to me but I’m no professional. IF those pressures were ever present on a factory 700 SA what would it do to one? Just trying to wrap my head around the statement he made cause it doesn’t strike me as remotely accurate.

 

[hollowoutadime]

Blind the shooter would be my guess.

 

[THEIS]

I recently got an email from a gentleman who says a certain round that was designed for a delayed blowback style gun would cause excess chamber pressure in a bolt action rifle. He said in the range of 127,000 PSI. This sounds a but silly to me but I’m no professional. IF those pressures were ever present on a factory 700 SA what would it do to one? Just trying to wrap my head around the statement he made cause it doesn’t strike me as remotely accurate.

Hi,

Could very well end your life insurance payments!

Industry proof rounds are essentially 1.5x operating pressure.

So that M700 SA for 7.62 Nato would fire 2 proof rounds at about 90k psi.

ANYTHING above that would be like playing hot potato with a Black Mamba while running in Houston TX traffic blindfolded.

Sincerely,
Theis

 

[roostercogburn98]

So I was correct in my thoughts that 120k should hand grenade any factory rem700. Now let’s place the details game and see what the general consensus is.
The 5.7x28 round is primarily shot out of delayed blowback and has a proprietary coating that aids in slowing the extraction and ejection from those platforms. In no way shape or form does the chamber pressure exceeds 60k from my understanding and that is hot rounds. I may be over a few K in that estimate as well. IF the SS190 ammo was shot from a bolt action rifle, would that make the pressure spike into the ranges I stated from the original post? I know chamber has some to do with pressure but most of the pressure is set from the powder,bullet and seating depth of the round. According to his statement, simply taking a factory bullet and firing from a bolt action would make the pressure spike to 120k because the round was designed for delayed blowback systems.

 

[THEIS]

Hi,

IIRC in 2011 Savage made the Model 25 in 5.7x28.....
But to answer your question directly......Unless some crazy unseen circumstances; I just do not see a way for the 5.7x28 factory ammunition to reach those pressures under normal operating conditions.

Sincerely,
Theis

 

[roostercogburn98]

Hi,

IIRC in 2011 Savage made the Model 25 in 5.7x28.....
But to answer your question directly......Unless some crazy unseen circumstances; I just do not see a way for the 5.7x28 factory ammunition to reach those pressures under normal operating conditions.

Sincerely,
Theis

You are correct, they made about 5 guns which ended up in someone’s collection of memory serves me correctly. I am 100% certain it won’t cause pressure spikes like that. I have at least a thousand rounds ( factory and handloads) through my 5.7 bolt gun built on a 700 frame. I just respect most people’s professional opinion and knowledge here so I wanted to see what kind of replies I got here. I’m not the sharpest tool in the shed but was fairly confident that simply taking a bullet from one chamber to another wouldn’t spike pressures 2 plus times barring any crazy circumstances like you stated.

 

[Supersubes]

This gentleman you were talking to is an idiot.


Now let’s talk about your 700 based 5.7. Details please.

 

[Steel head]

This gentleman you were talking to is an idiot.

This!

 

[roostercogburn98]

This!

Built this a few years ago just to see if it could be done and be reliable. Keeps 1moa or better with hand loads. Have shot it out to 400 and kept it on steel. Anything past that is just wish my washy on accuracy. Steel pic is some groups. Bottom set is un suppressed and top group is canned.
-Rem700 SA
-Shileen 1:14 16 inch barrel
-PTG one piece bolt, sako extractor, badger bolt knob
-Magpul Hunter
-Timney trigger
-Leupold MK4/Badger rings
-Co uses my YHM phantom

 

[LeftyJason]

I recently got an email from a gentleman who says a certain round that was designed for a delayed blowback style gun would cause excess chamber pressure in a bolt action rifle. He said in the range of 127,000 PSI. This sounds a but silly to me but I’m no professional. IF those pressures were ever present on a factory 700 SA what would it do to one? Just trying to wrap my head around the statement he made cause it doesn’t strike me as remotely accurate.

You should write it up and add it to this thread.

https://www.snipershide.com/shooting/threads/whats-the-most-stupid-thing-youve-been-told.208181/

 

[Supersubes]

Built this a few years ago just to see if it could be done and be reliable. Keeps 1moa or better with hand loads. Have shot it out to 400 and kept it on steel. Anything past that is just wish my washy on accuracy. Steel pic is some groups. Bottom set is un suppressed and top group is canned.
-Rem700 SA
-Shileen 1:14 16 inch barrel
-PTG one piece bolt, sako extractor, badger bolt knob
-Magpul Hunter
-Timney trigger
-Leupold MK4/Badger rings
-Co uses my YHM phantom
View attachment 7194428View attachment 7194429View attachment 7194430View attachment 7194431

Cool gun. How’d you get the magazine to work?

 

[roostercogburn98]

Cool gun. How’d you get the magazine to work?

My magazine is a delrin adapter. I got the idea from my buddy who made his 5.7 from a Model 7. He made his adapter from aluminum. One day I’ll update mine but it looks fugly at the moment. I just got lazy because it works good and I have a ton of other projects on the stove

 

[Supersubes]

My magazine is a delrin adapter. I got the idea from my buddy who made his 5.7 from a Model 7. He made his adapter from aluminum. One day I’ll update mine but it looks fugly at the moment. I just got lazy because it works good and I have a ton of other projects on the stove View attachment 7194503

That’s cool. If it works well, run it. Delrin is a good material.

 

[roostercogburn98]

That’s cool. If it works well, run it. Delrin is a good material.

Yeah will more than likable new one from delrin as well. Just talking mainly cosmetics and making it look cleaner. The lines are off and it doesn’t it detracts from the gun as a whole in my opinion. Maybe I’m crazy but that’s my thoughts when I see it. Maybe a new stock and paint one day as well but that’s far into the future.

 

[hollowoutadime]

Some light reading on internal ballistics.

Internal Ballistics

Calculating Barrel Pressure and Projectile Velocity in Gun Systems | Close Focus Research - Ballistic Testing Services

closefocusresearch.com

 

[roostercogburn98]

Some light reading on internal ballistics.

Internal Ballistics

Calculating Barrel Pressure and Projectile Velocity in Gun Systems | Close Focus Research - Ballistic Testing Services

closefocusresearch.com

Only problem from my understanding is FN never released the 5.7x28 for SAMMI testing so there is no official PSI data available. Maybe some CIP data somewhere but once again from understanding that is driven a little more by law in Europe than safety? Someone please correct me if I am wrong.