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Martini International MKII Disassembly/Assembly with Pictures

3K views 11 replies 7 participants last post by  slamfire1 
#1 ·
I have really been struggling to get my trigger adjusted and in a repeatable fashion. I had gotten it down to 11oz but I could not repeat it after trying to work it lower, it seemed that something was holding the trigger spring up not allowing it to drop back when the trigger screw was backed out. I figured there was gunk in it, boy was that right. So my trigger went from 1lb 10 oz to 6lb 4 oz and I wanted to get it down to the 2-4oz level if Possible. There is one thing you can say about these triggers, they are incredibly consistent down to the 10th of an oz if you can test it that consistently.

After searching and searching with no luck on really detailed instructions I decided to just jump in and go for it. At first in looking at the trigger assembly it was a little intimidating as everything seemed to be spring loaded and some things come out differently than you would think. I did have the help of the parts schematic which is available on here as well as the Martini website. If you are wise you will take pictures every step of the way to have something to refer to. Here goes, hope this helps. Sorry the last picture is really the first.

1. Remove the trigger assembly.
2. Compress the exractor spring, coming apart you can just press down on it but going together requires a little more work. Remove spring and ejector retaining pin then the extractor.
3. Uncock the breechblock and remove the BB pin then the breechblock.
4. Remove the cocking lever pin then the cocking lever and tumbler. You will need to remove the lever out the top turning it when you get to the wide part at the bottom of the lever.
5. Remove the hammer pin then hammer and spring. Note that the hammer spring prongs ride over the top of the sear bushings.
6. Remove the sear pin and the sear and bushings. You would be wise to use a drift pin to push out the sear pin so that you don't lose the bushings.
7. Next you will Remove the trigger stop then the trigger pin and trigger. Once again the trigger will come out the top. The trigger weight spring will be left sticking up inside the housing, I actually made another lighter spring using Brownells spring stock.

You can disassemble the breech block if you want to clean it up but it's pretty self explanatory. I did clean mine as it has a lot of carbon and I also wanted to profile the striker. When putting the firing pin back in and the striker spring retainer note that they only sit correctly if you rotate them correctly. If they are 180 off you will see it. Look at it carefully before you disassemble.

I will put more pictures and assembly instructions in the next post. I was able by cleaning things up and putting a new trigger adjustment spring in to get the trigger to a scary 1oz - 15.3 oz on the top end which is fine with me. The trigger will not hold consistently when at this 1oz level but it will at just under 4oz without doing any other work. I do have another idea I will try when I get some time but that is for another day.
 

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#2 ·
Assembly

The assembly is just in the reverse order but there are a few things key.

1. If you disassembled the breech block make sure the striker retainer follows the rear of the block, this also goes for the striker face as well.

2.When disassembling and re-assembling quite often it is easier to use a punch or drift to align things the use the appropriate pin to push the punch out. This keeps springs and bushings in place.

3. Before putting each piece together test it out as much as possible. When I put the trigger together I feel if it's right, when the sear and hammer go in check to see that they hold and trip properly and so on.

4. Turner the cocking lever so the wide part goes through the trigger area, also make sure the tumbler goes up into the striker properly. Test it all when installed.

5. I used a spent casing and and card stock to compress the extractor spring in the vice. Look at the picture.

6. I try to always put small parts in tape and mark them so I know what the originals are.

I hope this all helps.
 

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#3 · (Edited)
Glenn.

Good work and always nice to know how the system works and goes together, however, a word of caution please.

If you set the trigger too light or incorrectly on Internationals then on a hard/snappy close of the breech block, the BSA will fire.

Commonly called an ND in police/mil circles.

Giz :)

Edit. See your ex mil Glenn so you know what an ND is..
 
#4 · (Edited)
Giz, I agree and that's why I said that I keep testing it as I'm working on it. Before when I adjusted it at a lot higher weight it would discharge when closing the cocking lever hard. This cleaned up a lot of that but the weight can go a lot lower than what is safe. I spent a lot of time working on it to get it right, it's not something you change and run out to the range without first a lot of dry runs.

I'm adding the rifle and parts breakdown.
 

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#6 ·
I have had the above illustration for years, and have been thankful for it as a guide. But it is a basic guide and leaves out many of the nuances of dis-assembly and assembly. It does help to add basic knowledge, but as with you, I had to dive in and experience the process. Also, it helped to have another complete action assembly to reference.:bthumb:
 
#7 ·
Thanks Glenn.

Break down parts as illustrated are always helpful to RFC members.

IMHO BSA Rifles are super old school cool; (don't own one presently although I borrow & shoot one regular), I love them to bits, rock solid construction & superb engineering, very little to go wrong if they are looked after properly.

Being polite (PC as they say today) they are ugly looking buggers at best, ungainly, overweight, reminds me of some old Russian Baikal shotguns.

The good news is; I love them, rock solid construction and weight helps, some are still accurate enough to give the big boys a run for their money.

Giz :)
 
#8 ·
Being polite (PC as they say today) they are ugly looking buggers at best, ungainly, overweight, reminds me of some old Russian Baikal shotguns.
You're entitled to your opinion, of course, but I'd disagree quite strongly with you on that.

They're not at all ungainly nor overweight for what they were designed for. If you ignore the buttstock and trigger guard of the Mark IV / V they have some nice lines on them - stock, cheekpiece, lever, trigger guard, loading trough, barrel, etc., and they were always nicely finished. I leave it to others with more experience of them to comment on Baikal shotguns.
 
#9 ·
Nice job, Glenn!
Methinks these things are nothing but glorified hole punches anyway so beauty is holes in the right place(s). ;)
 
#11 ·
Slamfire, I do a lot of triggers so it is pretty economical to buy the bulk tube of coil springs from Brownells. There are various sizes 12" long each and you can almost always find a spring size you want. If you don't do many just pm me your address and I will send you one. Its a enter at your own risk situation. I can leave it a little long in case you want it heavier.
 
#12 · (Edited)
Glenn: Thank you for the reply. Now that I know you are making your own, I will dig through my Wolff spring sets and see if there is one that is the correct diameter. If that does not work, I will contact you.

Besides the crud that had built up, was a spring changeout the only thing needed to reduce the trigger pull? Also, from what I read, you did not have sear over rides when closing the breech block.

I was able to acquire a MKII this year







and these are targets from the first match after lengthening the trigger pull to 14 1/4". I added a Freeland buttpad and a 1/2" spacer. The original trigger pull was 13 1/2" which is shorter than my normal smallbore prone rifles:

I removed the Unertl and installed a Redfield 3200.



I removed this sight off and reinstalled the PH25C I have. I did not know the PH25C was an 1/8" MOA sight and as I rotated the knobs, nothing seemed to be happening, so I took the sight off! Only later did I find the PH25C was not 1/4" MOA clicks!







A real limitation of this rifle is the heavy trigger pull. This is more or less fine when using irons but not when using a scope, and I would like to drop the trigger pull even more.
 
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