TC Contender in 25 ACP

  • Last Post 28 October 2014
Crooked Creek posted this 15 May 2012

Does anyone have any experience with the 25 ACP in a Thompson Center Contender, or any other platform with a barrel longer than the typical 2” found on most 25 ACP's ? I'm getting ready to venture into this territory with a 15” Contender barrel in 25 ACP. The barrel and a 6 cavity Lee mold are on their way to me. I'm thinking the loads can be substantially higher than the 15,000 psi loads in the various manuals, for speeds in the 1200-1400 FPS range with 50 Gr. cast. Any thoughts ?

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onondaga posted this 15 May 2012

I recommend starting out with a chronometer right at the beginning. It will help eliminate surprises in  velocity. That tiny capacity case can have abrupt changes in velocity and pressure. If you chrono your first load you will have a reference for that powder. Then you can use the free online reduced charge calculator and proceed from there with some confidence:


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Crooked Creek posted this 15 May 2012

Thanks Gary, I do plan to use a chronograph starting with max loads from various manuals and creeping upward about a tenth of a grain at a time keeping a close eye on primers and their pockets. The case is small but it will hold quite a bit more than the loads normally given. I may even try some slower (than Bullseye) powders than normally recommended. Rog

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72coupe posted this 15 May 2012

That sounds like an interesting project. I would be interested in your results. Please post as much of your results as you can.

Surely I am not the only one interested.

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Duane Trusty posted this 16 May 2012

Crooked Creek

You may be interested in the following site.>

I realize the 25 auto data refers to factory ammo, but you may find it of some use.

Duane Trusty



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Crooked Creek posted this 16 May 2012

Duane, Thanks for pointing me to that site....good/useful information there, both the velocity and energy conversion tables. Based on the 25 ACP factory loads tested, it appears the optimum barrel length is in the 14-15” range (ignoring the American Eagle load). This gives me even more confidence that I can get to 1200-1400 FPS with a little load and powder selection “creativity". This could be a fun project. Thanks again for the heads up, Rog

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Crooked Creek posted this 02 January 2014

 After about a year and a half of no activity on this project, I'm beginning to restart it and see where she goes.   After casting and sizing about 200 bullets with the Lee six cavity mold and .252” push through sizing die, I discovered (long story) that the bore of the MGM Contender barrel measures .257", as best I can tell since it is five grooves and tough to measure with a standard micrometer. MGM used a 25 cal. rifle barrel instead of one intended for the standard 25 ACP bore of .251".  I was concerned that there could be issues with the chamber now that I need to use bullets sized about .006” larger. I did not do a chamber cast, only the last two inches of the muzzle. I did have a small supply of 65 grain gas check bullets that I had cast (for a 25/35 win.) from a Lyman mold and sized in an H & I die set to .257". I loaded one of these in a 25 ACP case and it looked and chambered just fine. Apparently, MGM cut the chamber in anticipation of using the larger diameter bullet, but....that may being giving them a little too much credit for thinking ahead. This does present some problems in seating the bullets when the cases are “normally sized” in a Lee carbide loading die set. The flair is too slight to allow the .257” bullet to enter the case mouth. What I did was use a Lyman “M” die (just the tip of the expander) intended for a 6.5mm case to slightly “bump up” the mouth flair to accept the starting of the gas check. I had to sneak up on that very slowly/carefully as too much flair and the case wouldn't enter the Lee seater die. It worked well, but I had to seat the bullet all the way to the crimp groove before I could close the action on the chambered round. That doesn't leave much case capacity behind the bullet so loads with that bullet will be pretty meager. I also have a Lyman mold for a 100 grain variation of that 65 grain bullet, but I doubt that much powder could be put behind, since it would also have to seat to the crimp groove in order to chamber. Perhaps could get a mouse fart load out of it though. Most likely I will be better served sticking with the Lee 50 grain plain base bullet properly sized for the bore at hand. Back to the melting pot for another session. I think I prefer the H & I sizing/lubing to the tumble lube anyway.  I did buy one box (100) of Speer 35 grain Gold Dot bullets intended for the 25 ACP, just to see what kind of velocity I could achieve. But, since they are .251” I'm pretty sure the accuracy would not be acceptable, and see little point in pursuing that avenue.  I plan to try some powders that may not be traditionally used in 25 ACP short barrels, with the thinking being that my 15” barrel in the fixed breach Contender would allow a degree of latitude in both burning rates and charge weight. Based on what I've seen on the “Ballistics By The Inch” site, I think 1200 - 1400 FPS may be possible with the 50 grain cast.  I know this is an unusual combination and project, but if anyone has any words of wisdom or experience with the 25 ACP in longer barrels and stronger firearms (than blow back autos), I would certainly be open to any suggestions. 

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RicinYakima posted this 02 January 2014

Keep us undated, as I love adventures into uncharted territories! Ric

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Crooked Creek posted this 02 January 2014

 Will do Ric, thanks for the encouragement.  Since I'm going to be weighing and loading at the range, one shot at a time over a chronograph, varying the loads .1 grain at a time with a variety of powders, this is going to be a somewhat drawn out affair. I think I'm going to concentrate my immediate efforts toward casting and sizing a supply of the 50 grain Lee plain base bullets, and maybe a few more of the 65 grain Lyman gaschecks, and wait for a little warmer weather before venturing out to the range. So, it may be a little while before I have any meaningful updates, but don't give up on me, I'll get there eventually.  I forgot to mention earlier that I do have a small supply of the old Winchester 60 grain Open Point Expanding bullets (jacketed) in .257” for a 256 Win. Mag. Marlin model 62. These may make for an interesting combination being as how the barrel is .257"....I may just have to throw them into the mix to see what happens. 

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Brodie posted this 03 January 2014

Crooked Creek;  Just a note; when you are trying to develop a load in that “uncharted territory” watch you chronograph much closer than the traditional pressure signs.  The new pizeoelectric measuring equipment (which most of us can't afford) has proven (at least to me)) that the pressure spikes way before the traditional signs (primers, hard extraction, case head expansion) even begin to appear.    Brodie


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delmarskid1 posted this 03 January 2014

I've often wondered about the .25 acp in a bolt rifle. Please continue.

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.22-10-45 posted this 03 January 2014

Interesting project! Could this be called a rimless rook?

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Ken Campbell Iowa posted this 03 January 2014

i used to shoot the hornady 60 gr 25-20 mj sp bullet in my 257 wea ( g ) .. pretty accurate ..well the ones that made it to the target ... ( g ) .

i think you are having a lot of fun ...please keep sharing it with us peeping .. kens ..

i do think you are swatting at too many bumble bees at one time ...

how about slugging your chamber ...throat ...rifling ... and thus simplify that cloud of variables swarming y obscuring your project ..

and,as they say on science channel ...QUESTION EVERYTHING ! ..

my first ( and expensive ) custom rifle was from a well known gunsmithing house. i told them to short throat my 257 wea so i could load 75 gr. coyote bullets .. so no need to check that ... right ??

took me a year of 1.5 moa before i thought to check that little detail ... wea saami is about 1.0 inch freebore ... fooey ... oh well, a dandy 250 yd coyote rifle ... did you know that any smart coyote knows he can go 400 yards out and sit and flip you the bird ??

be careful of fast pressure rise .. i disintegrated a 22 lr marlin when that little case let go backwards ..made me a believer


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Crooked Creek posted this 03 January 2014

 I will be very careful, and rest assured I'm not trying to make this into an “Ultra Short 25 Magnum".  After seeing what factory loads can do in a longer barrel, on the BBTI site, I feel confident that in the Contender platform, velocities can be achieved that could make this a dandy squirrel, bunny and other small vermin hunting combination in a reloadable form...not that I am anti 22 rimfire in any way. It's just a lot of fun to create your own, and it's not something I would be shooting in any kind of “plinking” type volume like one may do with a 22 RF. When people say “why?", I guess it's just for the sake of experimenting and doing something that may not yet have been done...just because!  I'm hoping that accuracy will be pretty good, but that tweaking will come after finding the best powder/velocity combinations.  I fired a couple of shots into the ground in the backyard with the first group of undersized bullets. Recovering one and seeing very minimal rifling engraving is why I questioned if the bore diameter was of the 25 ACP standard of .251".  That is when I did a Cerrosafe cast of about 2” of the muzzle end and determined it is .257". So much for “assuming"! I guess it was much easier for MGM to get standard 25 cal. rifle bore diameter barrel blanks than seeking out .251” barrel stock. I may do a chamber cast, but I don't relish the idea of getting Cerrosafe stuck in the extractor cutout if I don't need to. So far, both fired shot extracted with no effort with a light contact of a cleaning rod. The extractor does not do a good job of “finding” that little semi rim of the very short ACP case, hence the cleaning rod extraction. Both cases were also “smoked” a little and the mouths of the fired cases would not accept a fresh bullets, so it seemed the pressures were pretty low. Also, the primers showed no indication of even beginning to flatten. Also, the twist rate measures at 10". Maybe the 65 grainers will stabilize well (?).  Not that I have anything against Bullseye, Red Dot, Unique, or others normally shown for the 25 ACP (I'll try those too), I'm just thinking that something a little slower on the burn rate might just work out better in the longer barrel while keeping the pressures acceptable. The Contender is far more capable, pressure wise, than any of the pocket autos where loading manual loads are intended to be used. While the case is very small, I have checked weighed the capacity with several slower (mostly ball) powders and it looks like there is plenty of room to work.  There are quite a few bumble bees, and the swatting may wear me out before I'm done, but I'm a long way from asking for mercy...just yet! I am retired, and the “soap operas” can only hold my attention for so long. 

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Ed Harris posted this 03 January 2014

In my Remington 580 single-shot boltgun chambered in .32 ACP I could get 1200 fps using a compressed caseful of #2400, about 6 grains, with an 82-grain LHP bullet. But 50 yard groups were about double what I got with the same bullet at 1040 fps with 1.8 grs. of Bullseye.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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wallacem posted this 28 October 2014

Don't know if you are still working on this project, I r4ead theu your reports, and wanted to suggest using paprt patching on the .251 size bullets. That can bring them up to correct size and seal good. Wallacem in Ga

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