not your average trigger questions (MKIII 22/45)

lindertw · Post by **lindertw** » Thu Jan 17, 2008 10:40 am

I hit the range today to test out my latest mods (including todays range time, I've got ~2250 rounds down the pipe):

adjusted overtravel & installed/adjusted pretravel on factory trigger
installed Clark hammer bushing and sear pin
slingshot mod
installed narrow aperture rear sight

The thrust of today's range time was to make sure everything still worked - a resounding yes

The difference with the pre/overtravel adjusted was surprising. My next planned mod is to install a RP trigger plunger spring and then I'll probably call it a day as I like the weight of the trigger pull.

Now onto my questions:

1) I shot 300 rounds of Federal 36gr bulk pack ammo (maroon box), and I experienced what I'll call a gritty/notchy trigger pull somewhere in the middle of the magazine. Rounds 1-3 were fine, somewhere in rounds 4-7 there was one or more gritty feeling pull, then the rest were fine, gritty feeling was gone.

I'm thinking maybe pieces of unburnned powder that go away with successive pulls of the trigger, or maybe the pretravel needs to be let out just a smidge? Any other possible cause? I've never touched the factory hammer/sear, and it seems to me if there was a problem with the mating surface of either it would be present with each trigger pull; and I don't recall it acting this way prior to the changes I've made...

2) The trigger pull on the last round of each magazine is noticeably heavier - I mean if I lose count, I know when I'm on the last round 'cause it's that much heavier. The pistol has exhibited this 'feature' since day one, and I thought it might go away when the mag safety went away, but it's still there. Is this normal?

here's a quick pic of my last target of the day. I need to work on shooting slower! Federal 36gr bulk ammo, 21' fired two-handed/offhand.

lindertw · Post by **lindertw** » Thu Jan 17, 2008 4:58 pm

mini-update: my Wolff RP trigger plunger spring arrived today, and after installation I recorded the following trigger pull weights (average of 10 pulls):

with empty magazine = 3lb 10oz
w/o magazine = 3lb 5oz

Assuming the empty magazine represents the condition of the pistol while the last round is chambered (ref question #2 in post above), where is the extra 5oz in pull coming from on the last shot?

recumbent · Post by **recumbent** » Thu Jan 17, 2008 7:05 pm

There is a protrusion on the back of the trigger body that goes into a recess in the front of the mag when the trigger is pulled.

What this does is if a mag is not fully seated into the pistol this protrusion will force the mag upward until it locks in place when you pull the trigger, when this happens you will experience a 10lb plus trigger pull.

When the mag is fully seated in the pistol this protrusion will rub very slightly against the sides of the cut out in the mag causing a slightly higher trigger pull with a empty mag in the gun versus with no mag in the gun.

This is the way it is on steel frame MKIIIs I would assume the MKIII 22/45 is the same.

I removed the trigger from my MKIII hunter and fired up the disk sander and ground it off. I have since replaced it with a Marvel MKII trigger. The MKII triggers did not have this.

lindertw · Post by **lindertw** » Thu Jan 17, 2008 7:27 pm

thank you - I'll put a little dykem on that bump and see how much I can shave to eliminate the problem.

appreciate the help!

Post by **Bullseye** » Fri Jan 18, 2008 6:55 am

Another possible source for the extra trigger weight is friction between the magazine body and the disconnector lever.

The gritty feel can be coming from unburned powder backblast finding its way into the trigger plunger. The resulting dirt will give the trigger a gritty feel. There used to be a product called a trigger shield that helped reduce the blowback from getting onto the top of the trigger body. These are not commercially available anymore. I have posted in the past that one can open up the trigger plunger hole diameter by a few thousandths and that can also reduce the gritty feel. The plunger only needs to be held captive in the hole to to its job of lifting the disconnector and returning the trigger fully forward. If the plunger has a little more clearance any powder residue on it will not cause a noticeable amount of drag. This will allow the gun to go a lot longer between cleanings and operate smoothly. If one decides to do this modification pay particular care while doing so in not deepening the plunger hole, otherwise the disconnector's operation may be affected.

R,
Bullseye

lindertw · Post by **lindertw** » Fri Jan 18, 2008 7:03 am

thanks for the reply Bullseye. After a bit of searching last night I did see a thread where you mentioned knocking down any ridges in the trigger plunger hole. It's on my list of things to tweak this weekend.

Glenn · Post by **Glenn** » Fri Jan 18, 2008 7:36 am

Welcome aboard! Nice 22/45.

Is that the real serial number?

lindertw · Post by **lindertw** » Fri Jan 18, 2008 8:08 am

Glenn wrote:...Is that the real serial number?

the S/N has been photo-shopped

Glenn · Post by **Glenn** » Fri Jan 18, 2008 1:03 pm

I usually pride myself in being able to spot chops...nicely done sir!

lindertw · Post by **lindertw** » Fri Jan 18, 2008 1:09 pm

Glenn wrote:I usually pride myself in being able to spot chops...nicely done sir!

lol, maybe next time I should clean up my grouping

Glenn · Post by **Glenn** » Sat Jan 19, 2008 7:48 am

HA! You never know, it may fool me!

lindertw · Post by **lindertw** » Sat Jan 19, 2008 1:12 pm

Had a bit of time today to tear everything down again...

I removed the bump from the back of the trigger with a file. I also rolled up 1000grit paper and knocked down the ridges in the trigger plunger hole.

Interesting to note that the Wolff RP trigger plunger spring is longer than the factory piece, which necessitated a tweak of the pretravel adjustment. Now both pre/overtravel are dialed in again and the trigger breaks at 3lb 5oz with or without the magazine in place

I'm heading to the NRA range this evening with a friend, and I'll see if the random gritty trigger pull is gone now that I dressed the trigger plunger hole.

My friend has a box stock MKIII slab side target gov't model. I expect he's going to want me work his over after he shoots mine and his side-by-side

recumbent · Post by **recumbent** » Sat Jan 19, 2008 2:05 pm

Good to hear you fixed the problem.

lindertw · Post by **lindertw** » Sat Jan 19, 2008 2:50 pm

recumbent wrote:Good to hear you fixed the problem.

and thank you for pointing me to that bump on the back of the trigger! It never really registered with me...

lindertw · Post by **lindertw** » Sat Jan 19, 2008 9:07 pm

shazam this little Ruger is really fun. Just got back from the NRA range and everything worked out very well. The gritty feeling is gone - most likely the ridges in the trigger plunger hole that are now history.

While at the range, I decided to try a few different brands of ammo. Now bear with me, as this is probably the most useless ammo test ever conducted as everything was shot offhand. Before you beat me up over this, I stink at shooting from a rest but I'll keep practicing, I promise

Federal Value Pack = $1 per 50 rounds
Aguila Super Extra = $2.15 per 50 rounds
Aguila Golden Eagle = $3.65 per 50 rounds
Eley Pistol Standard = $5.65 per 50 rounds
Eley Target Pistol = $6.50 per 50 rounds

each target = 10 rounds fired offhand from 21' (3"x5" cards, red sticker is 3/4")

The standout in my eyes from this test is the Aguila SuperExtra, I was able to keep tight little groups fairly easily and the price is right!

My range buddy bailed on me tonight, so I don't have another pistol to work on... Now that my project is set up like I want it, I'll proceed to shoot the snot out of her and see how tight I can get my groupings at longer ranges