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209 vs .25 ACP conversion

3 posts in this topic

Anybody messed around with the conversion?

Was it much help (less mess & better accuracy)?

"The conversion uses a breechplug that takes a 25ACP brass case with a rifle primer in place of the 209 shotgun primer. The result is a primer with less power and elimination of the crud ring that happens with a 209 primer and 777 powder. (the 209 primer also causes a similar fouling ring with other synthetics but 777 is the worst in my rifle). The 25 cartridge case is easier to handle than the 209 also due to increased length. When the inline manufacturers were looking for a more reliable ignition source the 209 primer was the only thing immediately available that would fit in the space available. With the 25 conversion you will have to load your own primers but the results are worth the effort. You can contact Precision Rifle. I'm not sure how many rifles they make a conversion for. I know they handle the T/C Encore, Omega some Winchester and some CVA and I expect others."

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Nobody has tried this?

From another site:

Search for ".25 ACP Breech Plug Conversion"


Too much energy:

A Thompson Center Encore was used to test the ignition energy between the 209 primers and the .22 Hornet rifle primers. A clean damp patch was push down to the bottom of the barrel with the ramrod. A 209 primer was ignited forcing the ramrod to jump 6”-8” up the barrel. The same experiment was done with the .22 Hornet with it's small rifle primer and the ramrod moved less than 1".

Eliminated unexplained flyers:

Personally, I believe these flyers were the result of the 209 actually lifting the sabot off the powder charge simultaneous with igniting the powder. The much milder Small Rifle primer of the Hornet case ignites the powder just as instantly but lacks the energy to move the sabot and bullet off the powder charge therefore eliminating the flyers.

Breech Plug Conversion:

To sum up, I love this conversion. The Encore is now perfectly clean inside and out shot after shot. I have eliminated the flyers caused by the excessive 209 energy levels. I find the shortened .22 Hornet cases very easy to install, remove and find in my pockets. One case has been primed over 40 times with the primer pocket fit as snug as it was when we first used it. We decap and prime the cases with the very economical Lee line of reloading equipment. As you lose them, you simply trim down another handful of .22 Hornet brass and away you go.

.25 ACP Breech Plug:

Originally, our Hornet conversion was embraced mostly by muzzleloader shooters who were also reloaders. As our market increased, more and more of our Hornet customers lacked the knowledge or tools or both to shorten the Hornet brass once they had needed more. Enter the .25 ACP or the .25 Auto. Rimless.

The .25 ACP breech plug works great. .25 ACP cases accept all small rifle and small pistol primers so the load development options are endless. The brass stay clean, extract with your fingers and also seem to possess unlimited life. The added bonus is they do not require any trimming. Just pop in a primer and insert them into the breach plug. The best results have been achieved using CCI 400 Small Rifle primers.

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I literally stumbled across this site the other day looking for a different muzzleloader for a friend, sounds interesting to say the least, also curious about their converted M77 Rugers and Rem 700 muzzleloader guns too.

Something I will look into for next year for sure.


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