Shooting cast lead bullets in a gas gun

[Herb]

In today's world my reserve of plated and FMJ 115 gr 9mm is running low. I can get many thousands in cast lead (lube groove).

HOWEVER: My Sig MPX PCC is a gas drive and port is close to chamber. Would these bullets cause a problem for a gas gun? How about Moly coated (also available)?

[Bdh821]

I would NOT recommend it. I don’t even run coated bullets through my MPX. 
 

IF you decide to try it, I’d say run hard cast lead at 18 brinell.  But your MPX will smoke like a musket with the lube
 

Good luck. Report back results 

 

 

My next question is how often do you take apart the gas system to clean?  That will play a big role on reliability. 

Edited September 18, 2020 by Bdh821

[Herb]

2 hours ago, Bdh821 said:

I would NOT recommend it. I don’t even run coated bullets through my MPX. 
 

IF you decide to try it, I’d say run hard cast lead at 18 brinell.  But your MPX will smoke like a musket with the lube
 

Good luck. Report back results 

 

 

My next question is how often do you take apart the gas system to clean?  That will play a big role on reliability. 

Never. Did break tail off piston at about 12k rounds. Disassembled and found piston running smoothly in its cylinder. Replaced piston and have run another maybe 3k thru it. Replaced trigger assembly with HyperFire 24C at about 1k rounds. Did get Sig to give me the new bolt carrier and firing pin at about 4k rounds. No other problems. Run Xtreme 115 gr HPCB at 1190 FPS. I will stay away from lead and moly.

[Bdh821]

Wow you’re lucky to have not had problems prior to 12,000 rounds!  I think the most I did was 5k without cleaning the gas system and it stopped running.

 

I clean my gas system every 1,000-1,500 rounds now 

[Chillywig]

Gotta keep your MPX clean to run reliably. I don't see a reason why you could not but would expect you'll have to clean it more often. I shoot blues out of mine exclusively without issues.

 

Used to shoot with a guy that shot hard cast lubed in a 40 cal G-Lock - his nick name was Kenny black powder Jones.... 

[Herb]

Bullet weight and velocity for those Blues? Chronographed? Thanks!!

[Chillywig]

147RN blues 3.1 Universal Win SPP 1.130 Labradar chrono Ave 926fps ejection 10ft at 2oclock from my gen 2 carbine

[Bdh821]

It's interesting to me hearing other peoples load preference.  I find 147s to feel sluggish in really any 9mm.   I'd prefer bullets to get to the target as fast as possible.  If I could source 100gr RN bullets, I'd use them.  For now, 1200fps 115s will have to do.  My ejection is about 20 feet around 2 oclock also.  Or off my right forearm as im a southie.