.25 ACP Breech Plug Conversion
 

T/C Encore modified breech plug to use .660" long .22 Hornet cases in place of the 209 primer.

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.   If you have the new T/C Pro Hunter or your muzzleloader is not listed below click here.

Extra .25 ACP brass (no additional shipping cost when ordered with breech plug):   

               $4.95 per 25, $8.95 per 50 or $14.95 per 100

Someone suggested that I put together a priming kit for the .25 ACP brass. Excellent idea, I wish there would have been one of these available when I bought my breech plug conversion. The kit contains 1 Lee Auto-Prime tool with two shelves; 1 .25 ACP case holder; 1 1/16" pin punch. Everything you need to prime your .25 ACP casings.

Now available, a .25 ACP brass priming kit.  This kit contains all the tools needed to prime and re-prime your .25 ACP brass.   See picture and details below:

Finally, a kit with all the tools necessary for priming those .25 ACP cases for use in the .25 ACP breech plug conversion! This kit is handy and so compact, you can take it with you to quickly and easily re-prime your casing whether on a hunting trip or just a trip to the range.  Read story below.

PELLETS VS LOOSE POWDER

Most bullets designed to shoot well in a 1 in 28 inch twist barrel will normally do so somewhere between 100 and 120 grains (always measure by volume) of loose Triple 7 powder.  Fact; Triple 7 loose powder is hotter than Pyrodex or regular Triple 7 pellets (this does not include the new Triple 7 Magnum pellets) by about 15%.  That means, shooting 2 of either of these pellets is equivalent to approximately 85 grains of loose Triple 7.  Shooting 3 pellets is equivalent to about 130 grains of loose powder.  This means by using 2 or 3 of the 50-grain pellets you will miss the window for best velocity and accuracy possible, IF your chosen bullet was designed to shoot well in a 1 in 28 twist rifle.

What determines how well a Muzzleloading bullet shoots?  By this, I mean, "What enables it to achieve its best velocity and accuracy?"  I believe it achieves this if it reaches the optimum rate of spin needed to stabilize it in flight (how fast you push the bullet through the barrel and the barrels rate of twist will determine how much spin is put on the bullet).  How does one know when this happens?  Well, I suggest one way to determine this is to start by over spinning the muzzleloader bullet (shooting it with too much powder) and measuring your 3 to 5 shot groups.  Be sure to follow a good in between shot routine or none of this will make any difference; click here to read the steps.  Back off on the powder 5 increments in volume shoot another 3 to 5 shot group.  Your groups will tell you when your muzzleloader bullet has reached its optimum rate of spin.  Normally the higher the ballistic coefficient of your bullet the more spin it will need to stabilize it.  I submit that if your Muzzleloading bullet is designed to shoot its best in a 1 in 28 twist barrel, this will occur somewhere between 100 and 120 grains of loose Triple 7 powder.

If I am correct, and I believe I am, using 2 or 3 of the 50 grain pellets misses the window for your best accuracy completely.

Now some are going to suggest using 2 50-grain and 1 30-grain pellet to fall within the window above.  That might work, but unlike loose powder, it does not allow for a 5 grain more or less powder test for best flight and accuracy.

Here is what Hodgdon's says about loose powder on their website.

• Triple Seven produces the highest velocities of all granular muzzleloading propellants when compared by volume (see Comparison Chart below). An added bonus is that this enhanced velocity results in a flatter trajectory and greater down range energy.
• Triple Seven works with all styles and brands of projectiles which makes it easy to find a load and maintain accuracy.

Enhanced velocity results in a flatter trajectory and greater down range energy... Wait, couldn't you achieve that with 3 50-grain pellets?  Velocity yes, but if you can't hit what you are shooting at...

Easy to find a load and maintain accuracy... Well, now isn't that what we are all striving for.  Why don't they say that about their pellets?  Because they know you can't do it with pellets.  Instead, ease of use is their selling pitch.

I submit that it would be nice if you could have both, but most of the time it just doesn't work out that way.  My assumption is that you are considering a .25 ACP Breech Plug conversion for two reasons; cleanliness and the best velocity and accuracy possible.  Why would you only go half of the way with a cleaner ignition system designed to allow your gun to achieve its best possible accuracy and velocity, by using pellets?  Take the leap to loose powder.  You won't be sorry you did.

Customer Testimonial:

Cecil,

Great to find a product that really works! I took my T/C Omega .45 with its new .25 ACP breech plug out to the range and had a group tighten from 5 inches to less than an inch, shooting 175 g Dead Centers with 105 grains of T7 FFg.

Thanks for your help.
Don Matheson
 

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