Accuracy work on Colt Trooper Mk III

[40-82 hiker]

I am bringing this post back due to work I just did to my MK III. Please see latest post...

My project with my Colt Trooper Mk III is coming along, and I am enjoying it very much. My loads are still more accurate than I am, so I'm leaving them alone for now (H&G 50, Bullseye 2.7gr, .38Spcl wad cutter brass). Firing single action, I am getting closer to holding the black of a 50 ft. NRA slow-fire pistol target at 50ft offhand, though not quite there yet. I am not dealing with DA at this time, as I'm leaving that for a little later. I am shooting it as much as I can, given my back and pelvis issues.

Here is the problem: I really am not happy with the trigger pull, as it is a little creepy, and the trigger weight is too heavy. I would like to know what work can be done before I talk to a gunsmith, so I am knowledgeable about what is possible to modify in the Colt, and what some realistic expectations can be with the trigger in SA and DA. In other words, I need to know what smoke looks like if I am getting it from the gunsmith, as I don't want to end up with a worse situation.

I know one response will be to just keep shooting the thing, and I am happy to say that is what I am doing. However, while it might be much to expect to get a trigger as good as the one in my Colt NM pistol, I do know the one in my Trooper Mk III needs to be better. I am very picky about triggers, and this one just isn't quite there...

Thanks in advance for any education...

[Scharfschuetze]

I used a Colt Trooper Mk III for a short while during my tenure with a Federal LE agency. I found it to be accurate enough and actually won the service pistol class at a state championship in the Southeast with it once. I shot it DA most of the time. As I recall its single action trigger pull was similar to your description. It just wasn't a Python or a S&W and I just learned to live with it till I could get a S&W from the armorer.

[Frank46]

Don't know if your trooper III has the set screw located on the underside of the trigger like mine in 357 mag. Forget which way you have to turn it but does lighten up the trigger. Mine actually has the best trigger out of all my revolvers. Frank

[40-82 hiker]

Don't know if your trooper III has the set screw located on the underside of the trigger like mine in 357 mag. Forget which way you have to turn it but does lighten up the trigger. Mine actually has the best trigger out of all my revolvers. Frank

Frank,

I looked and I do have a set screw on the underside of the trigger! Wow! Looks like I have a place to start. Thanks to you and Scharfshcuetze for the response. My Dad gave me the gun as he no longer shoots it (he never did really), so I never saw any instruction manual, and I sure didn't pay any attention to the set screw!

I did some research on the computer again (!) last night, and I found an article I had not found before. I cannot take any claim to it, and I downloaded it as text, losing the link in the process. IF this article is correct, the gunsmith at our LGS was ready to ruin my gun, as he said he could "polish" the trigger parts to make it better. I changed the font color on the pertinent part of these quotes from the article. I would think it possible to go outside of these specs, but I am ignorant of such work with this pistol. I may be in need of a good gunsmith experienced in doing such spring work on Mk IIIs, but for now will work with the set screw.

From the article:

"Trigger work on the newer Colt revolvers like the Mark III series and later is limited to installation of lighter weight mainsprings and trigger return springs. These usually come in kits with a lighter trigger return spring and several different weight mainsprings. Due to the very thin surface hardening of these models action parts, they CANNOT be polished or altered to give a lighter pull. Since these parts are made of high precision molded parts there are no machine marks or roughness, the critical work surfaces are already as smooth as possible and attempting to further smooth them will have no effect other than to ruin them by breaking through the surface hardening, exposing the soft steel underneath. Since the trigger return spring not only powers the trigger, it also powers the critical transfer bar which is also the revolvers safety device that prevents firing unless the trigger is deliberately pulled. Installing too light a trigger spring or altering a trigger spring can not only prevent trigger return, it can also prevent the transfer bar safety from working, resulting in an accidental discharge. In all cases of doing any trigger or action work on any Colt revolver the standards are that the trigger pull in both single action and double action cannot be below factory specified minimums, AND that the revolver be 100% reliable in both single action and double action."

Also:

"COLT TRIGGER PULL SPECIFICATIONS Factory specified trigger pulls for Colt revolvers are as follows: Factory specified single action pull: Model Minimum Maximum "D" frame .22 caliber 3.0 lbs 5.0 lbs "D" frame .32 caliber 3.0 lbs 5.0 lbs "D" frame .38 caliber 3.0 lbs 5.0 lbs Note: The Agent max is 7.0 lbs "E" frame .32 caliber 3.0 lbs 4.5 lbs "E" frame .38 caliber 3.0 lbs 4.5 lbs "I" frame 38 caliber 2.5 lbs 4.5 lbs "I" frame .357 caliber 2.5 lbs 4.5 lbs Factory double action pull. Maximum "D" frame .22 caliber 14 lbs "D" frame .32 caliber 14 lbs "D" frame .38 caliber 14 lbs "E" .32 caliber 14 lbs "E" .38 caliber 14 lbs "I" .38 caliber 12 lbs "I" .357 caliber 12 lbs Factory specified single action pull for the Mark III and later Colt's Minimum Maximum 3.0 lbs 5.0 lbs Factory specified double action pull for the Mark III and later Colt's Maximum 14.0 lbs."

[Scharfschuetze]

That's an interesting read. Glad you found that before you had issues.

I've seen that issue crop up with match AR-15 rifles and their shallowly hardened surfaces on their trigger parts. A good trigger pull would devolve into a stagy and creepy problem quickly. Gunsmiths quickly learned to re-harden the sear surfaces with a carbon rich paste and heat after the trigger job and in most instances that solved the problem.

[9.3X62AL]

I owned and ran a couple Mark III Troopers as duty guns early in my career. Their triggers were not as refined as those found on V-spring Colts or any S&W, but GOOD GRIEF these guns are STRONG and OVERBUILT. They are every bit as strong as an L-frame S&W, and their advancing hands and locking bolts are durable, unlike their counterparts found on V-spring Colts. They are "sleepers", and still can be had at gun shows for reasonable prices.

[40-82 hiker]

That's an interesting read. Glad you found that before you had issues.

I've seen that issue crop up with match AR-15 rifles and their shallowly hardened surfaces on their trigger parts. A good trigger pull would devolve into a stagy and creepy problem quickly. Gunsmiths quickly learned to re-harden the sear surfaces with a carbon rich paste and heat after the trigger job and in most instances that solved the problem.

I'll keep this in mind if my trigger pull starts degrading over time. Also, I think I'm still going to look for a competent gunsmith to set the springs right and check on the surface wear issue as well.

Thanks.

[40-82 hiker]

I owned and ran a couple Mark III Troopers as duty guns early in my career. Their triggers were not as refined as those found on V-spring Colts or any S&W, but GOOD GRIEF these guns are STRONG and OVERBUILT. They are every bit as strong as an L-frame S&W, and their advancing hands and locking bolts are durable, unlike their counterparts found on V-spring Colts. They are "sleepers", and still can be had at gun shows for reasonable prices.

Thanks. It does seem to be a very sturdy revolver. I'm taking this project on in part 'cause my Colt NM is giving be grief with retrieving brass from the ground as I get older (screwed up from a car wreck as a kid), and my Dad gave me this revolver a number of years ago but I have never done anything with it until recently. I'm just looking to get it as good as I can without too much money involved, hopefully. I'll still be shooting my NM, but on bad days (and good!) this one will be greatly appreciated.

Wish I had your experience shooting them! Working on it, though...

[Harry O]

I have a Trooper Mk-III. Have you slugged the barrel yet? I found mine to be 0.002" to 0.003" smaller in diameter than my S&W's. I was using 0.358" sized bullets. It did not give me accuracy as good as my S&W's. I started using some jacketed bullets 0.356" dia and the accuracy improved. I intend to make up some smaller dia cast bullets and try then sometime, but have not gotten around to it yet.

[40-82 hiker]

I have a Trooper Mk-III. Have you slugged the barrel yet? I found mine to be 0.002" to 0.003" smaller in diameter than my S&W's. I was using 0.358" sized bullets. It did not give me accuracy as good as my S&W's. I started using some jacketed bullets 0.356" dia and the accuracy improved. I intend to make up some smaller dia cast bullets and try then sometime, but have not gotten around to it yet.

I did not slug the barrel to determine the grove diameter, but the cylinder chamber throats are rather large, so I went with a .359" sizing die for my H&G 50 wad cutters (they still pass through the throats without much resistance at all). I use a rather soft alloy, which is SOWWs with 2% tin added, meaning there is just a very little amount of antimony in it. The accuracy seems rather good when I checked if from a bench, but I am dedicated to shooting it offhand, SA at this time.

Thank you for your info about your MK III. It will do me well to keep it in mind if I find my accuracy lacking to my ability when the time comes. At this time, the load is more accurate than I am, and I seem to be calling my shots correctly, which gives me confidence in my loads. I do manage to totally call a shot incorrectly on occasion, but that is my doing, not the boolit's. I managed to place one shot at 12 o'clock at the top of the target yesterday, but I came to the conclusion that the shot came from elsewhere and was not my fault. Not sure where it came from, as there were no other shooters at the range. My shot must have passed exactly through another hole. :wink:

Thanks.

[smkummer]

I believe you can get 2 lighter spring kits from either wolf gun springs or trapper. That is about all you can do to one of these. The lighter of the spring kits may not give reliable ignition with magnum primers in double action. I gave my son a 6" trooper MK III .357 for x-mas last year. Prior to giving him the gun, I hit a 16" metal plate at 200 yards with a 158 LSWC Lee cast bullet going out at 1150 FPS sized at .358 about 40% of the time from a rest, that was as good as my Python and Officer Model match guns. I had to hold over and guess where the shot would go at that distance. I can hit the same plate about 90% of the time at 100 yards.

[GabbyM]

********* my Colt NM is giving be grief with retrieving brass from the ground as I get older *********...Few weeks ago. I purchased one of those Cheep made in China (Caldwell) velcro strap on brass catcher bags with zipper bottom. For my AR-s. Surbrised me when the gadget actually worked the other day. Past experience years ago was most bags would send brass back in to jam the rifle. Bag was around $9. This is a big help as we shoot a lot out behind the poll barn in ankel high grass. We ran about eighty rounds through with zero issues. Never tried to fill the bag but did let it hold a full 20 round mag once. We may of just been lucky. I've aTrooper III in 357 mag. Two of the six chambers are fat. It's new to me and belonged to teh GF's late. My 38 Special laod leaded the two fat throats. Bought 600 new 357 magnum casses and have about 1,500 gas checked boolits sized .359" setting here that were for lever guns. Confident these will shoot and they are even soft enough to perhaps expand a bit. Have plenty of 2400 to send them along the way.

[Frank46]

I've only shot the trooper III with S&B 357 mag ammo. Actually for me that day was a good one except when my buddy said "don't screw this group up". I didn't and actually had a 5 round group that fitted inside the 2" red dot I was using as an aiming point. Truth be told I'm not the world's best revolver shot. Better with the semi auto's. Frank

[40-82 hiker]

I believe you can get 2 lighter spring kits from either wolf gun springs or trapper. That is about all you can do to one of these. The lighter of the spring kits may not give reliable ignition with magnum primers in double action. I gave my son a 6" trooper MK III .357 for x-mas last year. Prior to giving him the gun, I hit a 16" metal plate at 200 yards with a 158 LSWC Lee cast bullet going out at 1150 FPS sized at .358 about 40% of the time from a rest, that was as good as my Python and Officer Model match guns. I had to hold over and guess where the shot would go at that distance. I can hit the same plate about 90% of the time at 100 yards.

Thanks. The Wolff Gunsprings kit for the MK III is now ordered (I ordered it directly from Wolff). It is not very expensive at all (even by my standards). It comes with a lighter trigger return spring, and two hammer springs, 11.5 lbs. and 13 pounds. Their info states the factory spring is 16 pounds (or 16.5 ?). The hammer spring is an easy replacement for most anyone, but I'm going to take it to a gunsmith to get the trigger return spring replaced.

[Petrol & Powder]

I inherited a MKIII and it is a strong gun. It lacks the "V" spring lockwork of the older Colts but it has a pretty good action and the coil springs may prove to be more durable in the long run.
I totally agree with smkummer that replacement springs are about all one can do to improve the action. Despite Colt's cost-cutting measures with that lockwork, it turned out fairly well. I actually think the action is better than a lot of the older Colts and it seems to have way less "stacking" prior to release than most of the V spring models.
Al is correct that the MKIII's are sleepers. I prefer S&W and Rugers but if I was in the market for a strong but inexpensive .357; I wouldn't pass up a good MKIII.

[40-82 hiker]

Don't know if your trooper III has the set screw located on the underside of the trigger like mine in 357 mag. Forget which way you have to turn it but does lighten up the trigger. Mine actually has the best trigger out of all my revolvers. Frank

Frank,

Today was the first opportunity to shoot my MK III since I lightened the trigger pull per your description and suggestion. It made a very big difference. The SA trigger pull still has a little too much creep for me, but it is a much better trigger pull now. My 50-foot offhand SA groups did shrink today with the help of the trigger adjustment. For now my load seems okay.

It is going to take me some time to get used to shooting this revolver, as it just seems SO different than my Colt NM pistol. Going to be fun, though!

[Frank46]

I'm happy that little form of advice has helped you out. I only knew about the screw because mine has one and i called a gunsmith buddy and after telling him what I have he said to experiment with different settings on the screw. Frank

[40-82 hiker]

I'm back to fill in the blanks where I left this post. Thanks to all responding.

I ordered the WC Wolff spring kit for my Trooper MK III and installed two springs this evening. The kit came with two hammer springs, 11.5 lbs. and 13 lbs, and a lighter trigger return spring ("lighter", but no "pounds" associated with the it - it is obviously a lighter spring, however). I installed the lighter trigger return spring, and the 13 pound hammer spring (the factory spring is supposedly 16 pounds). While in the action I cleaned and lubed as it should be. There is no need to take the revolver to a gunsmith to replace the trigger return spring. I just looked at the action after I got the side plate off and it was very straight forward. It was a little awkward to get the return spring in, but nothing very difficult.

I can say that the trigger pull has a completely different feel for the better, but it will never break like glass. However, I dry fired it (with casings with spent primers) a few times, both SA and DA, and I am VERY pleased with the difference.

The hammer spring is very simple to swap, so I chose the 13 pound spring at this time as I am using it 100% SA, and being ignorant of such things I was just a little concerned about reduced lock time with the 11.5 pound spring. If anyone has any handle on this aspect I would appreciate your opinion. At any rate, it is a different gun. Period. Very different! I am very pleased.

This forum is just amazing!

Thanks again to all,
Bob

[pcmacd]

I've only shot the trooper III with S&B 357 mag ammo. Actually for me that day was a good one except when my buddy said "don't screw this group up". I didn't and actually had a 5 round group that fitted inside the 2" red dot I was using as an aiming point. Truth be told I'm not the world's best revolver shot. Better with the semi auto's. Frank

Sure wish I could just delete this post?

[samari46]

If I'm not mistaken the max pressure's for the 357 magnum are lower today than what they were when the Colt Trooper III's were made. same for the 44 magnum as well. Considering that they had to be built stout to handle the elevated pressures. Think that current specks calls for close to 36K for the 357 Mag and about the same for the 44 magnum.Frank

[sw282]

''High precision molded parts'' from post #4.. l had heard of the MKllls' molded parts. Just never saw it in print.. And maybe a couple decades before S&W introduced their much maligned and cursed injection M I M parts... Those 3 letters will literally send most cult Smith&Wesson collectors into convulsions with weeping, wailing, and gnashing of teeth;-) l have only owned a couple MKllls in my time.. 0ne was a 6'' 22RF finished in factory Electroless Nickel with Colt Medallion Pachmeyer grips... A most accurate Colt it was. A bit on the heavy side tho..

[9.3X62AL]

If I'm not mistaken the max pressure's for the 357 magnum are lower today than what they were when the Colt Trooper III's were made. same for the 44 magnum as well. Considering that they had to be built stout to handle the elevated pressures. Think that current specks calls for close to 36K for the 357 Mag and about the same for the 44 magnum.Frank

The pressure gradients were changed c. 1990 IIRC for the magnum revolver rounds, from a copper-crusher "Copper units of pressure" factor to a PSI rating. SAAMI and others explain that there is no valid method to "convert" CUP to PSI, and use some of the same language you see in comparisons of "weight" to "mass". Awright, fine. In any event, after the SAAMI re-work the gunmakers started chambering J-frame S&Ws in 357 Magnum and repro Winchester 1873s in 357 and 44 Magnum, a thing they DIDN'T do before that time. So, YEAH--the magnum revolver calibers have been toned down some.

I am not one to push the pressure envelope with most calibers. Specific to the magnum revolvers, 90% of my loading of the 357/41/44 mags (and the 45 Colt/Ruger) runs a standard-weight cast SWC of some kind in the 900-1000 FPS bracket. This is the realm of the 41 Magnum lead-bullet "police" loadings and the black powder 45 Colt loadings. These are accurate, useful, powerful, and easily controlled shooting loads, and can be fired all day if you are inclined to do so. I usually am. There are no esoteric powders being used here--Unique and Herco get the call here, and serve well. Data? in 357 mag, use 38 Special +P data for the bullet weight you are dealing with + 10% as a start load, and you will be close to your objective. 41 Magnum loads are published all over the place in this intensity. 44 Magnum is easy like the 357--use "Skeeter's Load" for 44 Special (7.5 grains of Unique) +10% in the Magnum case, and season to your own tastes from there. In 45 Colt, start with "book" loads for your bullet weights and in the Colt SAA/clones of same I stop at about 800-825 FPS with 4-3/4" barrels and 900-925 FPS with the 7-1/2" barrels. This might seem a little conservative in some quarters, but it gives a margin of safety where needed; I use this data in the S&W N-frame 45 Colts as well. If you are running a Ruger Blackhawk or Redhawk derivative, 9.0 grains of Unique gives about 900 FPS in my 7.5" Blackhawk and gave about 815 FPS to a Uberti Cattleman x 4-3/4". That was a "max" load in the Pasta Colta; it is a starting load for the Ruger Bisley BH. 10.2 grains of Unique gives right at 1000 FPS to both Lyman #454190 and #454424 (both 255 grain castings). 11.0 grains of Herco gives 1000 FPS or a bit more. In my revolver, I can't see a bit of difference between downrange results from the two loads--accuracy, velocity variances/spreads, recoil or report differential (both kinda docile). Have fun.