Is all powder combusted in the case?

Welcome to the Leverguns.Com Forum. This is a high-class place so act respectable. We discuss most anything here ... politely.

Moderators: AmBraCol, Hobie

Forum rules
Welcome to the Leverguns.Com General Discussions Forum. This is a high-class place so act respectable. We discuss most anything here other than politics... politely.

Please post political post in the new Politics forum.
Post Reply
User avatar
Tycer
Advanced Levergunner
Posts: 7690
Joined: Sun Sep 02, 2007 10:17 am
Location: Asheville, NC

Is all powder combusted in the case?

Post by Tycer »

So is all powder burned in the case and any unburned powder found in the barrel just a byproduct of initial combustion?
Kind regards,
Tycer
----------------------------------------------------------------
http://www.saf.org - https://peakprosperity.com/ - http://www.guntalk.com
User avatar
claybob86
Senior Levergunner
Posts: 1907
Joined: Mon Apr 02, 2007 10:41 pm

Re: Is all powder combusted in the case?

Post by claybob86 »

Pisgah just answered that a little bit ago:

viewtopic.php?f=1&t=76064&sid=cb54929e3 ... f40ad17572
Have you hugged your rifle today?
User avatar
Blaine
Posting leader...
Posts: 30495
Joined: Mon Dec 17, 2007 2:22 pm
Location: Still Deciding

Re: Is all powder combusted in the case?

Post by Blaine »

Tycer wrote: Sun Jan 19, 2020 8:35 pm So is all powder burned in the case and any unburned powder found in the barrel just a byproduct of initial combustion?
Every test/experiment I've ever read about, and there have been dozens, say the FPS increases with bbl length...Rifles, and handguns. A good, Factory Crimp like Lee helps.
The Rotten Fruit Always Hits The Ground First

Proud Life Member Of:
NRA
Second Amendment Foundation
Citizens Committee For The Right To Keep And Bear Arms
DAV
User avatar
DocRock
Levergunner 2.0
Posts: 217
Joined: Thu Oct 31, 2019 8:06 pm

Re: Is all powder combusted in the case?

Post by DocRock »

All powder is not burned in the case. Throat erosion is caused, in part, by the abrasion of as yet unburned powder. One of the reasons that Leverevolution powder does its magic is that it's delayed peak pressure means it's still burning in the barrel. And anyone who is a fan of IMR4227 knows that there will be powder combustion residue down the whole barrel because, in part, it isn't all combusted in the chamber. The amount of powder fully combusted within a given length is subject to things like total powder load, bullet resistance and crimp, bore size, and, of course, powder burn rate, along with ambient temperature, humidity and other factors.
User avatar
AJMD429
Posting leader...
Posts: 31939
Joined: Sun Sep 09, 2007 10:03 am
Location: Hoosierland
Contact:

Re: Is all powder combusted in the case?

Post by AJMD429 »

Even if all the powder burns 'in the case', the pressure would still accelerate the bullet more with each added inch of barrel. If some is still burning as the bullet goes down the barrel, all that would do is smooth the pressure spike somewhat. There will always be 'extra' pressure coming out after the bullet exits, but as to whether there is ever still-burning powder at that point I sure don't know. Others here think there is not, and I'm willing to believe that, but regardless of that, as long as there is still pressure behind the bullet pushing it out, the shorter barrels will be noisier and lose velocity.

We have all seen the 'ball of fire' exiting the muzzle with some loads; whether there is still burning powder there or just glowing hot gasses I don't know.
Doctors for Sensible Gun Laws
"first do no harm" - gun control LAWS lead to far more deaths than 'easy access' ever could.


Want REAL change? . . . . . "Boortz/Nugent in 2012 . . . ! "
User avatar
GunnyMack
Advanced Levergunner
Posts: 9940
Joined: Mon Sep 19, 2016 7:57 am
Location: Not where I want to be!

Re: Is all powder combusted in the case?

Post by GunnyMack »

I'm not a ballistician, nor do I play one on tv but a guy I knew developed a porting jig for shotgun barrels. His testing showed most available powders suitable for shotguns was finished burning around 16". He found through testing by drilling lots of holes in lots of shotgun barrels where the sweet spot was to reduce recoil while not loosing velocity. Rifle cartridges use more powder normally so yes it is burning in the barrel.
BROWN LABS MATTER !!
User avatar
JimT
Shootist
Posts: 5468
Joined: Thu Sep 06, 2007 5:04 pm

Re: Is all powder combusted in the case?

Post by JimT »

From my Ballistician friend ..

How the charge ignites and burns, in a rifle load:
The flash from the primer ignites granules that were within about ½" of the flash hole (does not matter much if the charge is compressed or not -- the flash drives everything into the front of the case and ignites only granules toward the rear of that mass). Then, hot gas from burning propellant can heat granules within a shallow rind of the unignited heterogeneous mass, to a depth of of, perhaps, ¼", enough to ignite those. Then, everything that is left (which is usually half or more of the total charge), ignites and burns along the exposed surface only. In a bottlenecked case, the shoulder often provides enough resistance to hold back a ring of unignited material as the core shears through and pushes the bullet down the bore. When this happens, the shear zone ignites and then those surfaces begin to burn. As you well know, granules that are pressed against the case walls and bullet base never complete combustion before the bullet is long gone.

Some of this came from Rheinmetall where that company installed windows in barrels and used high-speed photography to monitor the progress of the heterogeneous mass of unignited propellant, as that pushed the bullet down the bore. The rest from my testing with progressively thicker layers of inert simulant under each of the dozens of propellants I tested, and many of those tested with every primer known to man. If the simulent was 0.4 inches thick, all charges ignited every time; when I went to a 0.5-inch thick layer of simulant, I got exactly one ignition -- A #7, of all things -- only one load of three but that one did ignite (primer type did not matter at all, which did not surprise me -- the hotter primer simply compresses the charge faster and more violently and therefore seals off the permeability faster so the hot gas cannot penetrate enough deeper to matter).

Fun stuff!
User avatar
Tycer
Advanced Levergunner
Posts: 7690
Joined: Sun Sep 02, 2007 10:17 am
Location: Asheville, NC

Re: Is all powder combusted in the case?

Post by Tycer »

Just got off the phone with Hodgdon. The tech said it would take a six foot barrel to capture all the burning kernels. The powder absolutely continues to burn outside the case.
Kind regards,
Tycer
----------------------------------------------------------------
http://www.saf.org - https://peakprosperity.com/ - http://www.guntalk.com
User avatar
Tycer
Advanced Levergunner
Posts: 7690
Joined: Sun Sep 02, 2007 10:17 am
Location: Asheville, NC

Re: Is all powder combusted in the case?

Post by Tycer »

Excellent Jim!!
Thanks
Kind regards,
Tycer
----------------------------------------------------------------
http://www.saf.org - https://peakprosperity.com/ - http://www.guntalk.com
User avatar
AJMD429
Posting leader...
Posts: 31939
Joined: Sun Sep 09, 2007 10:03 am
Location: Hoosierland
Contact:

Re: Is all powder combusted in the case?

Post by AJMD429 »

Cool....it's fun learnin' stuff.... :mrgreen:
Doctors for Sensible Gun Laws
"first do no harm" - gun control LAWS lead to far more deaths than 'easy access' ever could.


Want REAL change? . . . . . "Boortz/Nugent in 2012 . . . ! "
User avatar
gamekeeper
Spambot Zapper
Posts: 17326
Joined: Thu Sep 06, 2007 3:32 pm
Location: Over the pond unfortunately.

Re: Is all powder combusted in the case?

Post by gamekeeper »

After watching folks firing Mosin-Nagant Carbines it looked like ALL the powder was burnt OUTSIDE of the barrel...... :lol: .
If more men loved and cherished their wives as much as I love bacon the world would be a much better place.
User avatar
Rimfire McNutjob
Advanced Levergunner
Posts: 3144
Joined: Mon Sep 03, 2007 2:51 pm
Location: Sanford, FL.

Re: Is all powder combusted in the case?

Post by Rimfire McNutjob »

I think some of this is discussed in McPherson's last book. I think the closest you're going to get to having it all burn in the case would be a light load of Bullseye in a stright walled pistol case.
... I love poetry, long walks on the beach, and poking dead things with a stick.
User avatar
JimT
Shootist
Posts: 5468
Joined: Thu Sep 06, 2007 5:04 pm

Re: Is all powder combusted in the case?

Post by JimT »

gamekeeper wrote: Mon Jan 20, 2020 10:24 am After watching folks firing Mosin-Nagant Carbines it looked like ALL the powder was burnt OUTSIDE of the barrel...... :lol: .
My little .357 Magnum 5 shooter ..
FIRE.jpg
I believe it is possible that some powder is burning outside the barrel ...
You do not have the required permissions to view the files attached to this post.
Post Reply