Weatherby Vanguard Stuck Bolt

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The bolt of my customer’s Vanguard could not be manipulated following a range session. Here’s how the root cause was discovered and what it took to get the rifle functioning again. "The bolt handle is stuck," the customer said, handing me the camo-stocked Weatherby Vanguard chambered in 223 Remington. "And the trigger won’t move," he added. He was right; at first glance the bolt handle appeared to be in the up position but it didn’t look right.

He gave me the details, saying that they had been doing some recreational shooting the past weekend and after awhile experienced a few misfires; a click and no bang. They had been shooting a mix of ammunition, primarily 223 Remington but towards the end of the shooting they were working through some steelcased 5.56. Oh-oh. Now, steel cased ammo in and of itself is generally not a problem despite what the Interwebz may say. My problem is 5.56 NATO in a 223 Remington chamber. I tagged the Vanguard and set it aside.

A day or two later I took it up and tried to manipulate the bolt. It would partially close and all but The bolt handle could be manipulated only about 1-1/2" up and down, but sequential repeated manipulations finally resulted in the bolt handle reaching the full lift position and allowing withdrawal from the action. lift to the full upward position but not quite enough to pull the bolt to the rear.

A few more manipulations and the bolt handle lifted all the way and I was able to pull it to the rear and release the bolt catch on the left rear of the receiver, withdrawing the bolt completely. The Weatherby Vanguard is like many other bolt action rifles, very similar in design, function, and features to the seminary Mauser Model 98, if differing in some details like not having a controlled feed extractor.

Removing the guard screws and taking the barreled action out of the stock, I removed the trigger assembly from the receiver and checked its function. All appeared to be in order with the fire control mechanism, and I was reminded once again at how—erm—"low cost of manufacture" the Vanguard is. Examining the bolt assembly and looking at the positional rela-

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In a normal situation, the striker spring force would be holding the cocking piece cam follower fast against the bolt body cocking cam. This photo could not be taken unless considerable counterforce was applied to the cocking piece sear to pull the cam follower away from the cam surface. Something was jamming the striker assembly inside.

The cosmetic bolt sleeve cover is setscrewed to the bolt sleeve shank. tionship between the components, the cocking piece follower was not in its mating groove at the top of the cocking cam and was partially rotated towards the closed position. The cocking piece follower was not in contact with the cocking cam in the rear of the bolt body; there was a gap of maybe 3/16" of an inch between the cocking cam and the cocking piece follower. "Broken firing pin," I thought.

The cocking piece assembly readily unscrewed from the bolt body and the firing pin tip was intact. Peering through the bolt body at a workbench light, I could not see directly through the firing pin passage. After placing a clean paper towel on the bench, the bolt body was upended and tapped on the towel. A number of tiny, dimpled discs fell out. Apparently, this Vanguard had become less of a rifle and more of a precision punch press.

After a thorough cleaning of the inside of the bolt body and lightly lubing the cocking cam, the bolt went back together without a hitch. The barreled action was still out of the stock at this point. After reinstalling the bolt assembly into the receiver, the bolt could be manipulated normally and the firing pin fell as the trigger was pulled. Three primed 223 Remington cases verified ignition.

While the bolt was disassemble d, diameter measurements were taken of the firing pin and its mat- Brace the bolt handle against the base of the right index finger and apply force to the bolt sleeve with the right thumb. ing hole in the bolt face. The cylindrical section of the firing pin tip measured 0.079" and the firing pin hole inside diameter in the bolt face was 0.081". Hardly what one would consider excessive clearance, or consider as a candidate for bushing the firing pin.

In fact, 0.001" clearance on each side of the firing pin is what many consider a practical minimum. Firing pin protrusion was also measured and found to be 0.043", easily on the

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The striker is cocked and the bolt can be reinserted in the receiver. This is a must for bolt-action rifles of cockon-opening design. low side of what one would expect as normal, however, the customer reported no failures to fire except when the bolt locked up. On the face of this objective evidence, it didn’t appear as anything was amiss with the rifle.

As a rule of thumb, a firing pin diameter of about 0.075" is generally considered to be suitable for cartridges developing up to and including around 50,000 pounds per square inch, give or take a couple thousand PSI or so, and about 0.062" for cartridges developing pressures higher than 50,000 PSI; the smaller What was disturbing was the customer’s use of 5.56x45mm ammunition during his informal shooting the prior weekend.

It is generally given that 223 Remington cartridges can be used in a 5.56-chambered weapon, but not the other way around. The slight differences in the neck and throat/leade areas between the two cartridges can cause pressure spikes when a 5.56x45mm cartridge is fired in a weapon chambered for 223 Remington, and I suspected that this might be the case with the customer’s Vanguard. I asked the customer if he had diameter firing pin and bolt face hole provides more support for the higher pressure.

Again, the measured 0.001" annular clearance between the firing pin and the hole in the bolt face didn’t raise my concern. some of the .223 and 5.56 ammo left, and he said all he had was some of the 5.56 rounds. He mentioned that his son picked up some empty cases of both and he dropped Discs of primer cup material apparently punched by the pressure of the 5.56x45mm cartridges.

The primer cup material against the firing pin along with the striker spring forced these through the firing pin opening in the bolt face to be deposited in the firing pin channel in the bolt body. Further objective evidence of this is the anecdotal observation of the customer’s nephew of the rifle’s striker being cocked immediately following making a shot and prior to manipulating the bolt handle. some of each off. The fired primers in the 223 Remington cases appeared normal, not flattened.

On the other hand, the 5.56 primers were flattened, with primer cup flow around the firing pin indent. None of the empties the customer brought in, either .223 or 5.56, had the center of the primer cup missing. The primer cups in the 223 Remington cases were nickel-plated, whereas the 5.56 primers had a brass/gold color to them. Examining the dimpled discs removed from the inside of the Vanguard’s bolt under magnification after solvent-assisted ultrasonic cleaning, every one of the discs was brass-colored.

This suggests that they were primers from the 5.56 ammunition that blew out at the dimple. When the customer came to pick up his rifle, I asked if he or any of the others in his group experienced anything unusual when shooting the Vanguard, such as more force required to close the bolt, a puff of gas, or hot burning particles to the hands or face, etc. He said it seemed the 5.56 ammo "took a little more force" to close the bolt sometimes.

His nephew made an observation that after firing around, he noticed the cocking piece was to the rear of the bolt shroud and the bolt handle lifted more readily than usual, indicating the firing pin was cocked just after firing and before opening the bolt.

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Recall that the Mauser 98 and its progeny are of a "cock on opening" design. It’s been observed by others that a blown primer can cock the firing pin of a bolt-action rifle—gas pressure impinging on a blown primer cup disc in contact with the firing pin forces back the striker, causing the sear surfaces to engage and the primer cup punching is forced past the firing pin tip and into the bolt body.

I showed the customer the cause of the problem, the little pile of dimpled primer cup discs that jammed up his rifle’s bolt, and said that based on the objective evidence the 5.56 ammo in his Vanguard as currently chambered effectively converted the rifle into a precision stamping press.

I explained the theory behind the root cause of the problem, that being the necks of the 5.56 cases fitting tightly in the chamber and the case, thus gripping the bullet and causing ignition pressure of the 5.56 rounds spiking higher than that of the 223 Remington ammunition with blown primer cup discs the result. I sent him on his way with his rifle and the recommendation of keeping to 223 Remington ammunition for the Vanguard, saving the 5.56 for his AR-15.

AG This was not the case with the blown primer cup discs jamming the striker assembly. The firing pin tip projection measured 0.043", a bit on the low side of what many consider normal. The No. to the slotted setscrew that locks the trigger housing screw in place. When removing a Vanguard’s trigger housing from the receiver, remember to loosen this setscrew first and then tighten last. American Gunsmith Reader Services 1.