Buckmark Field Model Rail

My back up gun is a Buckmark Field model with a full length rail. I have notice that the 3 screws with the lock washers tend to loosen up over a short period of firing. I'd rather stay away from Loctite as the rail must come off for any kind of barrel/action maintenance. Meaning that the Loctite has to be cleaned off the threads and reapplied each time the rail comes off with overnight setting, etc.

I have read that one can apply a strip of nail polish across the top of the screw from one side of the screw to the other overlapping the rail and that will hold the screw in and will give a visual indication if the screw is backing out. The nail polish is easier to apply and clean off as compared to the Loctite variants.

Is the nail polish method workable for this application and is my reasoning sound? I do not as a rule get ham-handed in torqueing the screws. I do mount a dot to the rail and I would rather keep the dot mounted when removing the rail.

Personally I would use the correct Loctite (they have a laundry list of variations) over nail polish. In this case I would use 222 (purple) and a small amount. Loctite is designed for thread retention, where as nail polish is a cosmetic and often contains components that are abrasive. It would work in a pinch but far from ideal.

You might want to try ditching the lock washers. They are an attempt to add tension to keep the screw threads from walking, but they often accomplish the opposite. With no washer, the screw will stretch slightly, this will often hold much better. Clean the screw and the hole with acetone before tightening.

Be sure the screw doesn't bottom out in the hole, with or without the washer. Common source of this.

Yes, what they said! 
1) Ditch the washers and trim the screws if they bottom out (few pulls on the file)
2) Purple loctite is low strength and can be easily unscrewed. Blue loctite is medium strength removable without needing heat, but you do need a good contact on the threads.

Rails without loctite tend to "walk" in my experience.  What you think is tight today losens up with temperature changes and stress of recoil. So I would combine method 1 with purple loctite and call it a day.

This was recommended by a company that makes RMR sight plates. 

https://www.vibra-tite.com/products/threadlockers/vibra-tite-vc-3-threadmate/?cookie-state-change=1616172786181

On my Field Target, the order of doing up the screws mattered.  I took off the barrel, tightened those two first (purple Loctite and star washers), started the barrel screw, then did the rear post mount and finally did up the barrel fully.  I never had it come loose.  I reused the star washers because I could see small indents in the soft rail so I knew I would get better "bite".  I eventually bought replacement star washers (eBay?) cheaper than the OEM ones.

USE THE WASHERS !! - - Or the screws can gall into the Al rail & never come out.
Use the washers - Clean & install the front 2 (barrel) screws using the right loctite (I used blue). Snug them down nicely-tap the rail a few times & resnug. Let it sit for 24 hours. Mine never loosen. But they will come out if needed- no need to ever remove the rail from the barrel, unless replacing the barrel.
The rear rail screw?: they always loosen.
Part of my shooting routine is snugging it down about every 30 shots. No problem & the pistol disassembles easily for cleaning.
2¢

Russ OR wrote:USE THE WASHERS !! - - Or the screws can gall into the Al rail & never come out.
Use the washers - Clean & install the front 2 (barrel) screws using the right loctite (I used blue). Snug them down nicely-tap the rail a few times & resnug. Let it sit for 24 hours. Mine never loosen. But they will come out if needed- no need to ever remove the rail from the barrel, unless replacing the barrel.
The rear rail screw?: they always loosen.
Part of my shooting routine is snugging it down about every 30 shots. No problem & the pistol disassembles easily for cleaning.
2¢

There should be no reason for the rear rail screw to need "sungging" down every 30 shots or so or for it to always loose. If I am going to use Blue or Purple Loctite to two of the screws, adding one more is worth the time. I would rather keep/devote my match concentration on shooting not counting, checking the screw, etc. really don't to add to my process. So it I can eliminate it I will.

I do intend to keep the lock washers. Despite what some others have said.