Jack's Pressure Pad - RimfireCentral.com Forums

Go Back   RimfireCentral.com Forums > >

Notices

Join Team RFC to remove these ads.
 
 
Thread Tools Display Modes
  #1  
Old 12-01-2008, 07:24 AM
RimfireCentral

Join Date: 
Nov 2000
Posts: 
33
TPC Rating: 
100% (1)
Jack's Pressure Pad



Log in to see fewer ads
Submitted By: Jack

My secret weapon! It might even be an original idea ... wouldn't that be neat!

Most of us know that one of the keys to making the Ruger shoot is finding the just right amount of upward pressure under the front of the barrel. I know that there are other bedding techniques that work too. But I tried this, it works for me, and why fix what ain't broken?

About 18 months ago I had a Hogue stock on my rifle and found that as I changes shims between the front of the barrel and stock or increased the torque on the action screw that I would change the point POI and group size. I got some great groups but every time I tore the rifle down to clean it I had to spend too much time re-tuning to get the group size down. That 24 pitch screw the factory installed just wasn't conducive to precise adjustments. Results were fine, it just wasn't quickly and easily repeatable.

Being an engineer I reasoned that I could get the same results with finer adjustment by installing another screw under the barrel in the nose of the stock that pushed up on the barrel. About $3.00 in parts and 1/2 hour in the work shop later I discovered that I was right. I now use a Fagen laminated sporter stock (more stable than 1 piece wood stock) with a threaded sleeve about 1 inch back from the nose of the rifle stock (barrel channel was relieved to make sure that is no contact between the barrel and stock), a fine pitch set screw in the sleeve and a plunger on top to support the barrel.

Now when I put the rifle back together after cleaning I torque the action screw to 20 inch pounds and the barrel tension screw to 17 inch-pounds and like magic the POI is exactly the same and the rifle shoots less than 0.30" (outside edge to outside edge) groups at 25 yards.

Here are the instructions if you want to do it for yourself. Go to the hardware store, Lowes, Home Depot, etc. and buy 3 things.

1. Threaded press-in or screw-in sleeve. Theyre available in many flavors. I choose the stainless screw-in version.
2. The longest allen head set screw that will fit the interior machine threads of the sleeve.
3. A nylon bolt with an unthreaded shank that has the same or slightly smaller OD than the threaded sleeve.

Lets say that the stock is 1" thick (from bottom of barrel channel to bottom of stock) and that the threaded sleeve you bought is 1/2" long by 1/4" OD and that the nylon bolt has a 1/4" shank. You would install by:

1. Drill a 1/4" hole in the bottom of the stock into the barrel channel 1" back from the nose of the stock. Drill hole from the bottom to prevent the wood from splintering (if you apply masking tape to the stock before you drill the hole edges will be cleaner). Make sure that the hole is perpendicular to the barrel channel (use of a drill press is highly recommended).

2. Measure the depth of the hole (1") and counter drill a 5/16" hole, 1/2" deep from the barrel channel side. This makes the hole big enough for the shank of the nylon bolt to drop in without binding on the wood and leaves enough material to install the threaded sleeve flush with the bottom of the stock.

3. Measure the OD and thickness of the bolt head (should be about 1/2" x 1/8"). Counter bore the hole from the barrel channel to these dimensions so that the cut off bolt head and shank (see next step) drop into the hole and are flush with the bottom of the barrel channel. I should not here that I also opened up my barrel channel so that there was not metal to wood contact anywhere in the barrel channel. In other words if the action was strong enough to support the weight of the barrel, then the barrel would have been free floated.

4. Cut the nylon bolt off 1/2 inch from the top of the head. Then using a file or band saw, cut a "V" grove notch across the top of the bolt head. The notch should be wide enough to "cradle" the barrel giving it side to side support.

5. Drill a hole in the cut off bolt shank to accept the set screw. Make sure that the hole is centered in the bolt shank and aligned axially. Hole should be 1 drill size larger than the OD of the set screw so that the set screw threads will NOT engage in the hole.

6. Install the sleeve in the stock (press or screw in).

7. Install the bolt from the barrel channel side and insert the set screw from the bottom of the stock until the screw is bottomed in the hole in the nylon bolt. Measure and cut off any excess length (remember not to cut from the end with the allen).

8. Reinstall the action, barrel and barrel band if you use one. The barrel band should be relieved so that it DOES NOT contact the barrel when it is installed. IF everything fits a drop or 2 of super glue will secure the threaded sleeve to the stock and keep it from backing out. Be careful not to get any glue on the set screw or the nylon bolt.

Now, by turning the set screw in or out you can adjust the upward pressure on the barrel. Grab a few targets, lots of ammo and go start testing. Start with no pressure on the barrel and shoot a couple groups. Turn the set screw in 1/4 turn and shoot another group or 2. Turn the set screw in another 1/4 turn and try again. Keep good notes and the rifle will tell you what it wants. For me the difference was dramatic ... there were 2 specific settings between which the rifle shot markedly better. Once you isolate that pressure mark it so that you can find it again later.

I should also note here that you need to be able to tighten the action screw to the same torque setting as well. This doesn’t mean that you need to use a torque wrench, although that’s the best way. You can also make a mark on the bottom of the stock so that the screw head is always aligned the same, therefore the torque will be close. Also, this works best on a laminated wood or synthetic stock as they are the most stable and do not change dimensionally with changes in temperature and humidity. If you’re using a one-piece (non-laminated) wood stock it will help if you seal the stock with an epoxy or polyurethane finish.

Hope this helps.
Jack
 

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT -5. The time now is 02:51 AM.

Privacy Policy

DMCA Notice

Powered by vBulletin
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Search Engine Optimisation provided by DragonByte SEO (Lite) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright 2000-2018 RimfireCentral.com
x