Mk85 powder

[fliowa]

I use hundred grains of loose 777 ffg with Remington #11 caps in one of my MK 85’s. I still get a little bit of the crud ring. Gun is very accurate and has always fired. I have hunted with it in the extreme cold January’s of Iowa and the swamps of Florida.

 

[tpcollins]

I use a hybrid load in my grandson’s LKII (shooter version of the MK85). With #11 ignition, I put about 8 grains of Triple 7 down the barrel first that fills the flash channel of the breech plug. Then I pour 50 grains of BH209 on top of that, and use a Barnes 155gr TAC-XP with a polymer tip. The Triple 7 ignites the BH209 easily.

Shoots great and there’s a minimum amount of smoke. I don’t see a major reason why a little more BH209 couldn’t be used as long as it wasn’t excessive. If it cock’s the plunger on the recoil then I’d say you’re using a bit too much!

I think the barrel is 2” shorter than my MK85 so the charge is in the LKII about 10% less in time.

 

[toytruck]

You do know blackhorn 209 is not safe in a plunger gun, right?

 

[tpcollins]

You do know blackhorn 209 is not safe in a plunger gun, right?

Do you ever think about what’s going on with the breech, flash hole, flash channel, etc or just repeating what you’re read?

100 gr of BH209 has a muzzle velocity of around 1970 fps using a 250gr Barnes. 100 grains of Triple 7 push the same bullet at about 1897 fps. Do you really think all hell is going to break loose over 73 fps faster?

My hybrid load with 50 gr of BH209 on top of 8 gr of Triple 7 pushes the 155 gr bullet around the 1400-1500 fps if I recall. I’m not going to pee my pants worrying about it.

Actually Rom Laughton did some testing with a similar load using those same bullets that I sent him and they opened up like a flower.

 

[Confederate rifleman]

Its the pressure curve of BH209, not velocity or necessarily max pressures. Black powder, being an explosive, has a sharp spike and a uniform drop off in pressures. BH209 has a longer burn curve and exerts more pressure over a longer period. This overcomes the spring tension, weight and inertia of the striker and can and does occasionally, lead to blowing the striker back far enough to eject the primer and release a lot of gas.
If you want to shoot 209, get a rifle suitable for it before something unfortunate happens. Please.

 

[toytruck]

Do you ever think about what’s going on with the breech, flash hole, flash channel, etc or just repeating what you’re read?

100 gr of BH209 has a muzzle velocity of around 1970 fps using a 250gr Barnes. 100 grains of Triple 7 push the same bullet at about 1897 fps. Do you really think all hell is going to break loose over 73 fps faster?

My hybrid load with 50 gr of BH209 on top of 8 gr of Triple 7 pushes the 155 gr bullet around the 1400-1500 fps if I recall. I’m not going to pee my pants worrying about it.

Actually Rom Laughton did some testing with a similar load using those same bullets that I sent him and they opened up like a flower.

Go ahead be my guest!! Ignore Western Powders recommendations of a closed breech and 209 primer only statement. If posting in an open forum please at least put in a disclaimer so new members an folks starting out in this sport will know you are doing this on your own.

 

[tpcollins]

Disclaimer - don’t do what I do.

 

[Bill V]

Its the pressure curve of BH209, not velocity or necessarily max pressures. Black powder, being an explosive, has a sharp spike and a uniform drop off in pressures. BH209 has a longer burn curve and exerts more pressure over a longer period. This overcomes the spring tension, weight and inertia of the striker and can and does occasionally, lead to blowing the striker back far enough to eject the primer and release a lot of gas.
If you want to shoot 209, get a rifle suitable for it before something unfortunate happens. Please.

I have seen you post this info on more than one occasion. Can you post a link to substantiate this or is this something you read and passed along? Seems to me that it would require X amount of pressure to achieve X velocity regardless of the powder used. Would like to see a source for this info.

Bill

 

[Confederate rifleman]

Bill
Our own Sabotloader linked a chart on hunting.net on 4-8-17. I'm no good at linking from a phone...
The thread is " Blackhorn powder/ volume?"

 

[Confederate rifleman]

Even with smokeless powder in breechloaders, some faster powders will give the same pressures as slower burning, but not equal the velocity. The pressure isn't sustained for a long enough period of time. Longer pressure curve.

 

[tpcollins]

I have seen you post this info on more than one occasion. Can you post a link to substantiate this or is this something you read and passed along? Seems to me that it would require X amount of pressure to achieve X velocity regardless of the powder used. Would like to see a source for this info.

Bill

My exact point too Bill.

I would think the pressure from 50 grains of BH209 on top of 8 grains of Triple 7 ignited by a #11 cap pushing a lightweight 155gr bullet is going to create a lot less pressure than 100 grains of any ML powder pushing a 250-300 gr bullet.

But what do I know (disclaimer - don’t do what I do).