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Gbro · May 14, 2009, 05:57 PM

Last fall a very close friend and former Supervisor of mine experienced a miss-fire(failure to fire main charge) with his Mossberg 500A Muzzle Loader conversion. This is a 50.cal with a .209 primer.
http://www.mossbergs.com/manuals/Muzzleloader.pdf
He was loaded with 90 grains of loose Shockeys Gold FFg. and a 300 grain Hornady SST bullet (the one w/ plastic tip).
The primer fired when he drew down on a small whitetail buck @ 55yards but the main charge failed to fire. He was able to re-prime and again the rifle failed to fire(primer fired).
Taking the rifle back to the shack Mullin's was unable to pull the load with his ball puller because of the hard plastic point on the SST bullet.
Thinking maybe the powder somehow got damp and unable to remove the breach plug on this barrel, the gun was stored close to the wood stove to try and dry out what could be wet powder.
The next day the vent hole was picked and the gun primed. Again the rifle failed to fire. (The loading rod indicated a normal hunting load) in case you are wondering.

The rifle was re-primed and failed to fire several more times and then put aside for the bench at home.

Back home Mullins soaked powder charge as best he could through the vent hole and then tried everything he could think of to remove the breach plug and was unsuccessful.
He even considered heating the barrel with the muzzle pointed in a safe direction and then elected to make a long pilot bit and guide to bore out the point on the bullet.
The ball puller did not start in the pilot hole and a 3/8 inch drill bit was machined at the shank to tightly fit inside a 3/8" steel tube and loctite'ed into place. The complete plastic tip was removed from the bullet tip and again pilot drilled for the ball puller.
This worked, however the process of working in the area of a loaded barrel was not without concerns even though the powder was possibly dampened with penetrating oil, but the ball puller could now be threaded into the bullet which pulled out easily. .
Now the lesson learned was "not" to use this kind of bullet in this firearm.

Mullins now started loading this same gun with a 360 grain Norton ball (some think this is a minie), should he ever need to pull this ball his puller should do the job at camp.
Well Mullins did again experience the same miss firing.
This time the load was the Norton ball over 2ea 50gr, 777pellets. and again his 209 federal primers that he buys 1000 at a time.
Mullins re-primed this gun 11 (ELEVEN)times and picked the vent several times, each time the 209 primer popped with the noise associated with a pre-load primer firing.
The ball was pulled and the pellets removed. He had them at his bench today when I stopped for a cup of wife's Coffee.
I have a good idea on what is happening here, The picture of the 2ea 50 gr. 777 pellets might not show just how clean the pellets are. There was no indication any priming flame ever touched these powder charges. My friend was humbled to realize these 2 powder pellets overcharged his gun.
The breach plug in this conversion has a vent hole measured @ .025"

May 14, 2009, 05:57 PM	#1
Gbro Senior Member Join Date: February 20, 2005 Location: Minnesota Posts: 2,084	Failue to Fire, Mossberg 500A Conversion Last fall a very close friend and former Supervisor of mine experienced a miss-fire(failure to fire main charge) with his Mossberg 500A Muzzle Loader conversion. This is a 50.cal with a .209 primer. http://www.mossbergs.com/manuals/Muzzleloader.pdf He was loaded with 90 grains of loose Shockeys Gold FFg. and a 300 grain Hornady SST bullet (the one w/ plastic tip). The primer fired when he drew down on a small whitetail buck @ 55yards but the main charge failed to fire. He was able to re-prime and again the rifle failed to fire(primer fired). Taking the rifle back to the shack Mullin's was unable to pull the load with his ball puller because of the hard plastic point on the SST bullet. Thinking maybe the powder somehow got damp and unable to remove the breach plug on this barrel, the gun was stored close to the wood stove to try and dry out what could be wet powder. The next day the vent hole was picked and the gun primed. Again the rifle failed to fire. (The loading rod indicated a normal hunting load) in case you are wondering. The rifle was re-primed and failed to fire several more times and then put aside for the bench at home. Back home Mullins soaked powder charge as best he could through the vent hole and then tried everything he could think of to remove the breach plug and was unsuccessful. He even considered heating the barrel with the muzzle pointed in a safe direction and then elected to make a long pilot bit and guide to bore out the point on the bullet. The ball puller did not start in the pilot hole and a 3/8 inch drill bit was machined at the shank to tightly fit inside a 3/8" steel tube and loctite'ed into place. The complete plastic tip was removed from the bullet tip and again pilot drilled for the ball puller. This worked, however the process of working in the area of a loaded barrel was not without concerns even though the powder was possibly dampened with penetrating oil, but the ball puller could now be threaded into the bullet which pulled out easily. . Now the lesson learned was "not" to use this kind of bullet in this firearm. Mullins now started loading this same gun with a 360 grain Norton ball (some think this is a minie), should he ever need to pull this ball his puller should do the job at camp. Well Mullins did again experience the same miss firing. This time the load was the Norton ball over 2ea 50gr, 777pellets. and again his 209 federal primers that he buys 1000 at a time. Mullins re-primed this gun 11 (ELEVEN)times and picked the vent several times, each time the 209 primer popped with the noise associated with a pre-load primer firing. The ball was pulled and the pellets removed. He had them at his bench today when I stopped for a cup of wife's Coffee. I have a good idea on what is happening here, The picture of the 2ea 50 gr. 777 pellets might not show just how clean the pellets are. There was no indication any priming flame ever touched these powder charges. My friend was humbled to realize these 2 powder pellets overcharged his gun. The breach plug in this conversion has a vent hole measured @ .025" __________________ Gbro CGVS For the message of the Cross is foolishness to those who are perishing, But to us who are being saved, It Is The Power Of God. 1Corinthians 1-18 Last edited by Gbro; May 15, 2009 at 11:54 PM.