Handi Accuracy Discovery...

[hoytcanon]

If this tip is common knowledge and I have just managed to miss it all of these years, please excuse me.
 
For some time I have been making QD "tools-free" forearm knobs for my Handi rifles... Recently I made a batch of knobs and while doing so it occured to me that I would be able to control (to some degree) the forearm screw torque by adjusting the depth of the knob screw so that it "bottoms out" in the barrel lug and returns to the same (approximate) depth/pressure. So, I cut the 1/4" X 20 hardened steel stems slightly over length and gradually filed them down until I had the desired torque by bottoming out the knob bolt in the barrel lug. I tested this by dismounting and remounting the barrel between each five shot group and did this with three SB2 frames using two barrels on each frame and alternating barrels on each alternate group... the results were significant (although this is entirely subjective and inconclusive since it is based on experience and not empirical data)... my POI changed less than it ever has on barrel changes... paticularily when dismounting/remounting a single barrel (as opposed to different barrels). Note, I used the same barrel contours on the same frames for my casual test... example; with one frame I used a heavy .243 and a heavy .308, with another frame I used a standard contour .223 and a standard contour 7mm-08.
 

 
Maybe this will help out some other shooters with barrel swapping or dismounting accuracy. Good shooting. 
 

[quickdtoo]

See Forend Screw Stop in the Accurizing section of the FAQs, Larry recommended using a socket head set screw in the forend stud.

Tim

[cwlongshot]

Good Show!

I tried the set screw tip and while it was repeatable I found it easier to simply use dedicated frames. To those who do swap barrels it is a useful choice!

CW

[hoytcanon]

See Forend Screw Stop in the Accurizing section of the FAQs, Larry recommended using a socket head set screw in the forend stud.

Tim

This process is different than Larry's recommendation and superior in that the full threaded stud is being utilized, the base of the knob distributes the pressure over a greater area, on the hardened surface of the stock (as opposed to the drilled portion) and in a direct resistance motion, perpendicular to the barrel (rather than laterally as with the factory tapered screw). Also, there are less parts to mess with and/or loose, or possibly shift... I am going to experiment with bedding a pillar around the forearm lug hole (a washer could also be inlet into the forearm or simply surface mounted) and utilizing an adjusted length forearm lug screw (flat base, not tapered)... I don't always want a QD knob on my forearm... although the reason that I use a full 1" diameter knob is that I shoot with it in the center of my palm... it aids in repeatability (I find).
 
P.S - I was asked about the gun pictured in the opening post; it is a .30/30 with a DNZ mount and Mueller Multi-Shot scope and sports an 18" barrel with a Ross Schuler muzzle brake... that SB2 frame and Boyd's Sterling Thumbhole stock set (finished in textured black) was used in the above testing with another barrel, (pictured below)... the other barrel is a 7.62X39mm also 18", also with a Schuler brake and using a Weaver rail with Dura Sight Z2 QD rings and a Mueller Sport Dot scope (you have to look closely... different scope and mounts... if you have VERY good eyesight perhaps you can tell the diffrence between 0.308" and 0.310"!!!  );
 

[hoytcanon]

Good Show!

I tried the set screw tip and while it was repeatable I found it easier to simply use dedicated frames. To those who do swap barrels it is a useful choice!

CW

Thanks... but using a dedicated frame doesn't necessarily (probably not) solve the fluctuating torque problem,.. due to screws backing out... debris getting in between the forearm and barrel, swelling due to humidity and moisture (although synthetics are much better with this) etc... also, most people will at least remove the forearm once in a while for thorough cleaning... mine are off an on all the time... which is why this idea percoloated in my mind for awhile. I am sure some others must be in this boat also. P.S - C.W, I see you share my affinity for rimfires and shorties also!        

[cwlongshot]

P.S - C.W, I see you share my affinity for rimfires and shorties also!     

I have a "few" shorties (Levers, Single shots, Bolts and Pumps) and a few more rimfire's...(Single shots, Autos, Bolts, Pumps and Bolts)

CW

[peak98]

HoytCannon
Any clue on how much  torque (foot/inch pounds) gave you the best degree of accuracy ?

[hoytcanon]

HoytCannon
Any clue on how much  torque (foot/inch pounds) gave you the best degree of accuracy ?

Nope... this test was solely for consistency and returning things to the same set-up and POI... I did not test fire as I was adjusting the screw length... although that would be easy enough to do at the range also, by firing and filing as you go... once you file too much though, you would have to start over with a new screw.

[jparedes]

Hoycanyon,
Excellent idea.  I'm on my way to Ace Hardware to get some screws for this project.

[LaOtto222]

I like your solution, but as most cases, there are more than one way to skin the proverbial cat. It is a matter of what you feel comfortable with.

I pillar bedded mine so the pillar "bottoms out" against the lug and I use a button head screw for a Allen wrench. I also have a dedicated fore end for each barrel. When I snug up the button head screw, the relationship between the barrel and the fore end is repeatable because the pillar sets on the lug the same each time. You can increase the torque and the relationship between the barrel and the fore end stays the same. While a knob is very convenient, I just do not like the look, but it could be used with a pillar just the same.

BTW - I show how to do a pillar in the FAQ section. I think the relationship between the fore end cap and the frame are important too. By pillar bedding the fore end your fore arm and frame relationship can be maintained as well. Of course, it works best with a wood fore end where you can shim or shave the fore end/cap relationship to adjust this relationship.

Good Luck and Good Shooting
 

[hoytcanon]

I have noted considerable fluctuation in the forend cap to receiver relationship... Even with a fixed fulcrum and single screw anchor the forend can be shifted from side to side on assembly... For years I have been diligent to (attempt) to center the forearm fit, on assembly, by placing my thumb and fore finger on either side and holding the spacer centered while locking down the forend and tightening the screw... I pretty much have the process and consistency down... But even with all diligence there is some degree of lateral movement... It would be interesting to range test if there is any practical difference, on paper, between a centered forend and one intentionally misaligned?

[gcrank1]

As much as some of my factory plastic forearm spacers are 'off center' I thought is was intentional  .......
I let the durn things center themselves up (no tension) and tighten the screw. After a few shots Im sure the recoil and vibes have settled everything where it 'wants' to be. They seem to shoot where they are pointed......works for me, YMMV.