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Another Savage "Smokeless"
    Model 10ML II Blows!
How unnerving do you think it is to have a muzzle-loaded pipe bomb go off just inches from your face? 

The blown rifle in the above photo is what was left of a .50 caliber Savage Model 10ML II after a catastrophic failure of the rifle back in March of 2004.  Fortunately, no one was injured.  I know that for a fact - since I was the operator. 

Fortunately, the piece of barrel steel that's missing peeled forward and went down range.  I had other shooters on each side of me (public range), and if a piece of barrel steel had blown to either side, there could have been lethal consequences.   At least a half-dozen other shooters witnessed the incident, along with about twenty Missouri conservation officers who were at the range to qualify with their handguns that afternoon.  In fact, one I have known for years had been just visiting with me minutes before the rifle literally exploded.  Following are a few more photos of the blown rifle.
The section of barrel that peeled up and forward ripped the scope from the bases - actually tearing the front lens piece from the tube.  The front lens housing flew forward about 30 yards, while the remainder of the scope cleared the top of my head by mere inches - and landed in the parking lot 60 or so yards behind me.  I published these photos on this website in late summer 2004, and they created quite a stir. 

I'm publishing them again for a reason...and it's not to create another stir.  It's because I've been contacted by another Savage 10ML II owner who has had the same thing happen to him - and he was severely injured.
The shooter, who wants to remain anonymous for the time being, is from Canada.  He says he was shooting a Savage recommended "smokeless powder" charge and saboted bullet.   He also sent me four photos of his destroyed Savage 10ML II - and it shows all the characteristics of my exploded rifle shown here.  His rifle had been stocked with one of the "plastic" composite stocks - and it literally blew away the forearm section of the stock just forward of the receiver.  He had been holding the rifle with his left hand gripping the forearm, and the explosion mangled his hand.

This now makes four such incidents that I am aware of, two of which resulted in severe injuries.  The other injured shooter, from Tennessee, lost a thumb.  In 2007, he had sent me photos of his rifle and described what had happened.  And he wanted to know if I had any sort of analysis of what caused my rifle to explode in the manner it did.  I sent him my conclusions of what caused the rifle to fail - basing those conclusions on the evidence provided by the blown rifle, and from the gas cutting witnessed on the other half-dozen Savage 10ML II test rifles I had on hand.  Apparently that shooter and Savage came to some monetary agreement, since I never heard from him again.  (In all, I put some 36,000 smokeless rounds through Savage rifles over a 4 year period.) 

The rifle that blew on me had more than 6,000 rounds through it.  However, I had replaced the breech plug after every 500 to 600 rounds.  But as I discovered the more I scrutinized the blown rifle and the other Model 10ML II rifles I was shooting at the time - replacing the breech plug DOES NOT remedy the design flaw that is built into this high pressure muzzleloader. 
My Findings - For The Injurred Canadian 10ML II Shooter
The scope on the author's Savage Model 10 ML II was blown into two pieces - the rear section flying 60-plus yards into the parking lot behind him.
The missing piece of barrel steel broke loose at the back and peeled forward, breaking off and flying in that direction - preventing injury to shooters that had been on each side of the author.
First, take a look at the two breech plugs in the photo at the left.  The breech plug shown on the right is the standard Model 10ML II breech plug design used by Savage Arms.  Note how the breech plug is only threaded at the rear - with half of the plug left unthreaded.  The other breech plug, which is threaded all the way forward, to the sealing shoulder, is the breech plug designed by William "Henry" Ball - who took the smokeless muzzleloader design to Savage.  Again, I know, because I made that trip with Henry.

The Ball breech plug shown here came from a custom .50 smokeless muzzleloader that Henry had built for me, using a Howa center-fire bolt-action receiver.  The very plug shown here had been used to ignite and contain right at 8,000 smokeless powder rounds - and there was not the first sign of gas cutting on the sealing shoulder (the flat surface just below the short snout, which fits up inside the bore about 3/8-inch).
Now, take a look at the photo at right.  This shows the "sealing shoulder" of a Savage Model 10ML II breech plug.  You can easily see all of the gas cutting radiating out.  And this is because Savage's redesigned breech plug, to facilitate making the rifle for a few dollars less, gives the high pressures created by smokeless powder loads an airspace to flow back into.  And that space is the .010" to .015" void that surrounds the unthreaded front half of the breech plug. 

At most, the point of contact at any part of the circumference of the two opposing shoulders (sealing shoulder of the breech plug and the corresponding shoulder at the rear of the bore) is only about .050" wide.  That's right, the contact metal-to-metal seal that has to contain 40,000 to 50,000 p.s.i. pressures is only about the thickness of a dime in width.
The original breech plug design taken to Savage was threaded all the way to the front, left plug shown.
Brand new, right out of the box, the seal likely does that just fine.  However, it doesn't take a great deal of shooting before signs of gas cutting reveal that the pressure is flowing back into the airspace around the front of the breech plug.

One hunting buddy of mine had bought a new stainless steel Model 10ML II, and enjoyed shooting the rifle so much that he put around 600 shots through the muzzleloader in about 2 years.  When I began to notice the cutting on the "sealing shoulder" of the breech plugs I checked - I called and asked him to pull his plug.  He called back and said that there was definitely some cutting.  He had a new spare plug, so sent me the one he had taken out.  Then, about two months later, he called to let me know the new plug, after about 250 shots, was already showing signs of cutting.  I told him he needed to send the rifle back to Savage and have them check the "sealing shoulder" in the barrel itself.  They sent him a brand new rifle.  We took the rifle apart, and examined the shoulder of the breech plug and the shoulder at the front of the breech plug recess in the barrel.  Both shoulders were fine.  Some 300 shots later, light gas cutting marks could be seen on the shoulder of the breech plug.  So, he installed a new plug.  Just 200 shots later, the same cutting signs appeared again.  And with yet another new plug installed again, he has now only put 50 or 60 rounds through the rifle and reports that he can see light traces of gas cutting. 

The shorter life of the subsequent NEW breech plugs installed can be attributed to the fact that cutting has also occurred on the shoulder at the rear of the bore - meaning that a full 100% containment of the pressure is no longer possible.

Once the seal is lost, that airspace around the unthreaded front half of the breech plug becomes subjected to the same pressures as the barrel just ahead of the breech plug - where the charges of smokeless powder are ignited.  And with recommended powders like Vihtavuori N110, some loads approach and even surpass 50,000 p.s.i.

Go back to the top of this page and scrutinize the photo of my blown Savage Model 10 ML II.  Note the barrel threads ahead of the receiver.  Savage uses a barrel nut to tighten the barrel in place (which was blown into two pieces when the rifle exploded) - this makes it easier for them to headspace their center-fire
cartridge models, and this feature was simply carried over to their muzzleloader line.  Also, in the same photo, where the missing barrel portion allows us to look inside the breech plug recess, you can see that there are unused threads for the breech plug ahead of the threads on the rear portion of the breech plug.  Now, notice that from the bottom of the outside barrel threads to the bottom of the unused threads found in the airspace that surrounds the front (unthreaded) half of the breech plug, the barrel steel is only about half as thick as the barrel steel ahead of the breech plug recess.   Still, when the seal is lost between the front sealing shoulder of the breech plug and the corresponding shoulder at the rear of the bore, that thinner steel is subjected to the same high pressures as the barrel at its thickest point.

This barrel ruptured at this point (over the unthreaded front half of the breech plug).  The only thing that kept the entire rear portion of the barrel from coming apart was the receiver.  And the barrels of the rifles that exploded on the Tennessee and Canadian Model 10ML II shooters show the exact same characteristics.  And both of those rifles had less than a hundred rounds fired through each - which indicates that the seal at the front of the breech plugs in those two rifles was not sufficient when those rifles were shipped from the factory.  As little as a .001" to .002" gap at any point between the two sealing shoulders allows the high pressures of smokeless powder loads to flow back into the void around the front half of the breech plug.

The original Henry Ball breech plug, with threads all the way to the sealing shoulder, eliminates an airspace into which the pressures can flow into...thus also eliminates the dangerous gas cutting.  I brought this to Savage's attention back in 2004, and they still continue to build the Model 10ML II as if there is not a problem.  And shooters are being injured.  Perhaps it will take a fatality before the company makes the rifle right.  -  Toby Bridges
If You Know Of A Model 10ML II Rifle Failure, Please Drop Us A Line At-
The gas cutting seen on the "sealing shoulder" of this Savage Model 10ML II breech plug is proof that high pressures are escaping rearward into the airspace around the front unthreaded half of the breech plug.
Published 6-15-09