Large Rifle Magnum Primer

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A few years ago PRbullet came out with adapters one could use to utilize large rifle primers in one's muzzle loader. Breech plugs were modified so these adapters would fit, and they worked good.





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The adapters are stainless steel, and are very very durable. Because the adapters are stainless, the don't 'crush', and most all the time there will be blow by. This blow by can be cured by utilizing an o-ring. The adapters are a larger diameter than shotgun primers. The primer socket in breech plugs needs to be enlarged for these adapters to fit. This can be done with a 9/32" end mill. One also uses the end mill to make the socket deeper so that one's rifle will go into battery when the o-ring is in place. Another thing done to the breech plugs was to enlarge the flash hole to 0.034". The adapters fit a 22 Hornet shell holder, so they can be easily primed, with any standard priming tool. Spent primers are easily removed in any standard press.

The large rifle magnum primers were tested in sub-zero weather more than once, and there never was a problem igniting Blackhorn powder, after the loaded rifle was left out over night. Unlike shotgun primers, the magnum large rifle primers do not erode flash holes. After 700 shots, measured flash holes were exactly the same as they were at zero shots. It seems like the adapters, and the breech plugs will last forever. ☺
 
Am using a this metric o-ring 1.5mm thick with ID of 4.5mm, and an OD of 7.5mm. Don't really know how many shots they are good for, but would guess maybe 25 to 35 shots? Have used Winchester, CCI, and Federal magnum rifle primers; they all work. The Federal 215 primers leave a soft residue in the flame channel; i like that best.

One needs to take care not to make the primer socket too deep. If too deep the firing pin won't hit the primer hard enough to ignite it. My goal is make the socket 0.75mm deeper than factory. If the socket is too shallow, the 0-ring prevents the rifle from going into battery.
 
Had to bump this back up because its been a topic of discussion lately. Plus i found these and others pretty similar. Just seems to me like this type of washer might be useful for 17 cents each if they last a few more shots.
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You still have to have headspace perfect for your particular primer to use them. Been down that road over 10 years ago. Not with Variflames, but 209 primers.

The o-ring gives you a lot of flexibility for headspace, and from primer to primer.
 
Scott, the mill used to modify the plugs here, has a little run out. Most drill presses probably have a little run out. The plugs shown here have primer sockets a little too big for the plastic washer. The QRBP has a primer socket for the adapter that is 0.285" diameter. The Omega plug has a socket diameter of 0.284". Seems the washer wouldn't stay in place........

Would there be a washer with a slightly larger diameter available?







Had to bump this back up because its been a topic of discussion lately. Plus i found these and others pretty similar. Just seems to me like this type of washer might be useful for 17 cents each if they last a few more shots.
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Scott, just thought of this from years ago. Aluminum washers that were used with the pop-rivet tool, and fasteners failed rather quickly when tried as a shim under primer. If aluminum failed; perhaps the plastic isn't worth the effort? The aluminum washers seemed like a real good idea, but alas........
 
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