A Nurse with a Gun

Wednesday, November 12, 2008

Ruger MKII Blast Shield

Some of the dirtiest ammunition available is 22 long rifle ammo, and with the high volume shooting that a 22 pistol usually endures, crusty black dirt accumulates in any 22 pistol. Click to enlargeThe Ruger MKII is a well designed and durable firearm, but it does have it's weaknesses. One of those is the reputation for developing a gritty trigger over time. The reason is simple really, the upper portion of the trigger, the trigger plunger and the disconnect are all exposed underneath the feed ramp. As the pistol is fired and the brass ejected over time, soot, grit and dirt coats all of these parts and makes for a gritty trigger.

To solve the problem on my MKII pistols, I decided to fabricate and install blast shields for the triggers. I went to the local hardware store and purchased some brass shim material that was approximately the same thickness as a soda can. In the past, MKII shooters have actually used the aluminum from soda cans, but I wanted to start out with flat straight metal. Click to enlargeI also wanted to use a slightly different design than what others have used.

Instead of making a loop that fits around the grip frame lug, I made a tongue that would fit in the receiver recess on top of the lug. This had the advantage of helping to tighten up the pistol. The light gauge brass shim material is easily cut with sharp scissors. No tin snips are necessary. The tongue extending down into the magwell should have a curvature to it. Burnishing the underside of the curve will help the brass shield retain the curvature. I used hemostats as a bending brake to make nice well defined bends, including the compound bend necessary to fit the piece into the receiver recess. Make certain the disconnect and bolt hold back lever do not bind with the blast shield. Only a small amount of clearance is necessary.

Once I had the first blast shield fabricated, I used it as a template to fabricate blast shields for each of my Ruger MKII pistols. Click to enlargeBefore the pistol is reassembled with the blast shield in place, the trigger and action should be cleaned. If the grime is really caked on, only a detail strip and individual parts cleaning will do. If the pistol is not too dirty, a spray with Gun Scrubber and a bit of toothbrushing should do the trick. Once the parts are clean, lubricate them and install the receiver assembly back on the grip frame with the blast shield in between. Insert an empty magazine to check function, and then a full magazine for a live fire test.

The same technique can be used on the Ruger 22/45, and the MKI and MKIII pistols. The brass blast shield makes a protective shield that effectively keeps the dirt and grime off the trigger. Hopefully it will be years before my Ruger MKIIs develop that gritty feeling again.

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13 Comments:

Blogger dropdownstairs said...

Well, thats an encourgament to us all
now from poking around for blast shield found a link to a speed loader for the mkII ever use one?
http://tinyurl.com/6zfzga

ever try a marvel 22 lr conversion for the 1911? can shoot bulleye w/ it they say...

9:39 PM  
Blogger dropdownstairs said...

Well, thats an encourgament to us all
now from poking around for blast shield found a link to a speed loader for the mkII ever use one?
http://tinyurl.com/6zfzga

ever try a marvel 22 lr conversion for the 1911? can shoot bulleye w/ it they say...

9:39 PM  
OpenID curtislowe said...

That's awesome! I've never even heard of that. Learn something new every day.

How about posting a template?

9:46 AM  
Blogger Andrew said...

Any chance you could scan and post a picture of the shield?

A template for the rest of us would be a gift!

9:56 AM  
Anonymous tjm said...

just wondering, would the mag catch on the tab that hangs down into the mag well? i would think when you inserted the mag it would catch on it as it went up? i don't have a ruger yet but this was interesting so i figured i would ask. thanks

10:34 AM  
Blogger Unknown.Rodent said...

I have one of the the speed loaders you referenced. They work well saving my fingers a lot of abuse.

12:08 PM  
Anonymous FatWhiteMan said...

It will take me longer to re-assemble my MKII than to fabricate and install the blast shield.

12:31 PM  
Blogger Xavier said...

tjm, The tab fits in the recess behind the triggerguard. It does not bind.

3:53 PM  
Anonymous Jeff said...

Thanks Xavier! I'd wanted to do that but forgot about it, my suppressed MKII has a scary amount of blow back into the receiver, I have to detail strip it every other time I go shooting.

As far as the "Ultimate Cliploader" goes...

If you have a Ruger .22 pistol you need to buy one.

It's one of the best gun accessories I've ever bought, (If you don't count suppressors) totally worth it.

1:08 AM  
Anonymous Anonymous said...

Brass on steel in a hot humid environment? That will cause differential metal corrosion. Keep an eye open for rust in the future.

11:25 AM  
Blogger Xavier said...

Perhaps...... I had the option of stainless, but did not like the brittleness. Perhaps the brass shield will not corrode any more than the brass does in the chamber. Time will tell.

11:35 AM  
Anonymous Anonymous said...

Xavier, a template would be a nice thing to see you post. Any possibility? I think that the blast shield is just as important as a shim to tighten up frames and receivers as it is to protecting the trigger mechanism. The less you have take down a Ruger type pistol the better.

12:50 AM  
Anonymous Anonymous said...

This also works with the AMT Lightning and the AMT Baby Automag since they are almost identical to the Ruger MK I and MK II.

12:26 AM  

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