Contra-Testing Free Floating

[Ned Ludd]

Their tape is the main part of what’s inside the channel. No joke ).

I used to see rimfire shooters over at the CZ forum at Rimfire Central talk about gluing/setting their barrels rigidly into the barrel channel fairly often. They claimed it worked very well. Your results seem to suggest that dampening barrel harmonics within the first 12 inches or so of the barrel in front of the action doesn't ruin the precision either. In fairness, some of the CZ rimfire rifles in which these guys were bedding the barrels have stocks that extend almost out to the muzzle, so they were effectively bedding almost the entire barrel. Along this line, I have often wondered if one drilled a hole in a foot square solid block of barrel steel, cut rifling into it, then installed an action sticking out the back, how it would shoot. That would effectively remove much of what we perceive as barrel harmonics.

BTW - since you seem to have also been thinking about Gorilla Glue products, even if not in quite the same manner, I'll be willing to settle for 2.5% of the net.

 

[davidjoe]

I have often wondered if one drilled a hole in a foot square solid block of barrel steel, cut rifling into it, then installed an action sticking out the back, how it would shoot. That would effectively remove much of what we perceive as barrel harmonics.

I’ve been quietly keeping to myself that exact same, huge cube of steel theoretical barrel, for years, on about four or five different subjects that arise in discussions here, most notably where adding and subtracting powder from a cartridge comes up, as it frequently does, and is said to necessarily do a number of things (nodes, positive comp), other than the plotting of a vertical line of impact straight up and down a target, which is realistically all that changing powder weights would do in a truly unmovable barrel.

 

[RegionRat]

Along this line, I have often wondered if one drilled a hole in a foot square solid block of barrel steel, cut rifling into it, then installed an action sticking out the back, how it would shoot. That would effectively remove much of what we perceive as barrel harmonics.

Pretty close to perfect for eliminating several of the significant mode shapes, while still allowing normal barrel manufacturing and chambering methods. Pretty much agnostic to everything but the ammo in these machines.

 

[davidjoe]

^ RR, aw man, I just yesterday, got done making up my mind, and putting in a PM note that I had all the rifles I needed…

 

[RegionRat]

LOL

Trust me, when you have burned up a pile of those barrels you wouldn't ever want to see one of them again....

Those guys that shoot unlimited BR come pretty close to the same thing, but they can move theirs around by hands. Mine were scaled to heavier calibers and it took lots of big guys or machines to move them.

 

[davidjoe]

LOL

Trust me, when you have burned up a pile of those barrels you wouldn't ever want to see one of them again....

Those guys that shoot unlimited BR come pretty close to the same thing, but they can move theirs around by hands. Mine were scaled to heavier calibers and it took lots of big guys or machines to move them.

All of what you say, makes them even more appealing.

 

[DaveTooley]

Several of us have played with putting barrels under tension inside large diameter aluminum tubes. It worked most of the time but was tricky to sort out issues. I did one where the barrel was under compression. It worked also. Other than a lot of expense and work none of it yielded an improvement in accuracy . It added complexity that when it didn't work was very hard to do a work around. Tuning as we know went out the window.

 

[davidjoe]

Even without the clamps, it’s definitely a task to tweak the channel fill so that the final barrel “weld” puts no positive angle on the barreled action. With clamps, now a negative angle has to also be considered.

The barrel “weld” to the channel once achieved, through heat cycles and the action screws’ continuous pressure, typically won’t let the barreled action fall out when inverted, even if the contact length is only a couple of inches. That’s of course without these clamps as this is the first time I tried them.

Here, there is more like 9 inches of channel contact. With this gun settling in and shooting, I don’t want to waste the effort and materials of maybe the best channel weld that I have attempted in the most “modest” stock choice I have, but I still want a comparison.

The compromise “partial” solution I have is to shoot the same company’s barrel, same reamer, smith, shooter, box of ammo and range day conditions, head to head, sometime next week.






This barreled action is a proven shooter in an F-Class stock, but I have yet to shoot it at all in this McMillan universal inlet, generously free floated stock.

The head to head has the potential to either quiet my curiosity about this, or add legs to my theory, for soldiering onward.

If this Defiance repeater action, free floated, essentially matches my 40-X, well, that’s basically that, free floating a long, heavy barrel doesn’t detract from accuracy relative to bracing and dampening one. If it beats the 40-X, same thing. I will have it on a Phoenix bipod with a top tier scope.

If the 40-X beats this McMillan/Defiance, with the same ammo, shooter and same barrel, against a stock that is better, with a very fine action and lighter, arguably superior Jewel trigger, then the next step may very well be to shim the McMillan gun’s barrel and see what it does.

 

[davidjoe]

The .243 gun that I consider the real “control” gun, if those two rifles above don’t sort out a whole lot, or all of this, I don’t shoot at 100, but I know that it performs at 600 very well and wins the typical club matches I use it in.

It is not free floated, but it comes a lot closer to free floating with only about a single 3/4” or 1/2” wide strip, below, than it does to what I did to the 40-X.









Conceivably, it could be shot at 100, as a comparison between a pure FClass setup and - I’m predicting, an old 40-X on a Harris bipod. Likely I will shoot that 40-X in the next 600 to compare it to the F-Open gun, going the other way, which most recently shot a 447/450 - 22, though the problem with that is different conditions.

 

[David Milisock]

I don’t know exactly what to expect, here, but I’ve been curious about this subject for at least a decade. I’m wondering if anyone has tried this, or has any hunches, as I have just assembled it and not tried it yet.


View attachment 1450468

This is a 40-X with a fast twist straight 6mm chambered in .243 Win. It is not the .243 40-X that is shooting well in the Manners F-Class stock, that gun is undisturbed.

Along the lines of pre-stressed concrete beams, I have carefully filled an opened barrel channel with the correct amount of semi-compressible fill, such that once compressed initially with C-clamps, and finally with strap clamps, the action is flat (or will be after heat cycles), and the barrel is being pressed very tightly into the stock, contacted and semi-surrounded by dampening material. This is tricky.

View attachment 1450474

Plenty of times I’ve padded the channel for heavy barrels, but I have never pulled the barrel down from the top, and it is under significant pressure.


View attachment 1450475

Like action screws, these hose clamp straps can be tightened and loosened as desired.

The rifle is as “dead” as any I have handled. The goal, as always, is to shoot small, but I don’t know if it is a step forward or backward. It’s certainly a step toward my old Crosman.22 pump pellet gun, but I can’t say they were wrong regarding the strap.

Wow, pressure point on steroids, you may need to check the action bedding but in your case it's already good som maybe not. I use pressure points all the time on hunting rifles with great results, however the stocks on them usuallyneed help. I'm not sure what will happen to a rifle that already is goo.

 

[davidjoe]

Wow, pressure point on steroids, you may need to check the action bedding but in your case it's already good som maybe not. I use pressure points all the time on hunting rifles with great results, however the stocks on them usuallyneed help. I'm not sure what will happen to a rifle that already is goo.

If done completely perfectly, the idea would be that the action is neither pulled down nor pushed up by the barrel. It would however receive the benefit of a secured and dampened thick barrel helping to further locate and dampen it.

Imagine carrying a ten foot long 2” x 12” plank, but then three guys simultaneously grab onto it and start walking the same direction. Now holding on to the board actually helps stabilize your own walking.

On the 40-X, that marksman stock is original as it would have come many decades ago, except that they weren’t cut to allow a 1.25” bull, so I opened it up.

 

[David Milisock]

If done completely perfectly, the idea would be that the action is neither pulled down nor pushed up by the barrel. It would however receive the benefit of a secured and dampened thick barrel helping to further locate and dampen it.

Imagine carrying a ten foot long 2” x 12” plank, but then three guys simultaneously grab onto it and start walking the same direction. Now holding on to the board actually helps stabilize your own walking.

On the 40-X, that marksman stock is original as it would have come many decades ago, except that they weren’t cut to allow a 1.25” bull, so I opened it up.

I like the idea. It could better describes asca static support point.

 

[dgeesaman]

The action is tied to the stick, though, and most shooters would say that if any more of the action could be in contact with the stick, they would do it, some of the most accurate are glued to it.

We turn a 180 at the recoil lug. Behind the recoil lug, we want them anatomically connected, fused, molecularly, and in front of the recoil lug it’s diving board time. Two of them, really, free to resonate at will. And man do we spend a lot of time talking about the ostensibly solved issue of harmonics and resonance.

The logical difficulty for me is that the stock is strong enough to marry the action to, but where it is even thicker and more rigid, the fore end, which is exactly where the cantilevered barreled action is at its least rigid, well that would be a big “nah” on any contact, we’ll “pass”.

But boxing out structures that exists next to each other anyway, kind of like my car window is at its weakest, just before it’s all the way up into the frame, just hits me as mechanically sound, but at minimum, certainly not crazy.

I can understand that in the past, wood warped, small manufacturing variations would exert different amounts of pressure into sporter weight barrels that would give them different zeros, pressure screws and adjustable tensioning bands were patented at different times by at least Winchester, if not also Remington, and so forth.

There is certainly no easier manufacturing spec than “have a generous, non critical space between them” - but is is better? From the barreled action’s standpoint, there may as well be no forend.

Maybe ann answer is a rubber bladder inflated to an exact pressure before each shooting session, so you can control the exact force exerted by the stock.

 

[Brians356]

Thoughts:

1) This setup (or glued-in) should retard barrel cooling, and possibly promote uneven cooling, vs free-floated.

2) Once dialed in for a particular ambient temperature, how will a much different temperature affect accuracy and/or POI? (Thinking expansion/contraction of the metal straps.)
-

 

[leakeyjohn]

Seems to me that this validates view of mine I have come to. A well put together from quality components properly chambered, bedded, assembled etc will shoot well under a MOA. A rifle that was assembled to price point will show it in performance....

 

[davidjoe]

Planning to shoot more tomorrow. I’m thinking that these straps, as part of a pipe joint, made over real or synthetic rubber, are temperature stable enough to contain fluids at modest pressure when conditions change, by reason of allowing a person to tighten them down well beyond contact minimally necessary for pressure retention.

In other words, here, I could probably loosen the bolts as much as a full revolution, lengthening the strap by a worm screw thread width, but still have the rubber under reasonable compression, pressing the barrel down. Once the barrel has made its final impression in the channel material, that material becomes firm and doesn’t have much further movement to give, nor to rebound, whether the barrel exerts x amount of force, or 2x, or .5x, and so forth, at least within the range of variances of heat and pressure that shooting outdoors applies, from what I’ve seen.

The channel takes on the final consistency somewhere between say leather, and leather that has been used in a barrel vice several times to clamp a barrel for installation. The straps are doing two separate things, really. The steel strap pressure is essentially tightly bracing the barrel and forend against each other, ((we’ve seen downward whip in thin barrels) while the rubber “liners” inside the strap in combination with the channel fill are essentially vibration dampeners.

 

[davidjoe]

There was a .22 match going on until the afternoon, where is was 102, with loads appropriate for about 60, such that when both barrels heated up, pressure was not ideal for accuracy in either gun, but especially the 40-x. We are taking safety glasses being a must. But it was even.

I just walked from one bench to the other every three shots.






The defiance chamber was a tad tighter and I stopped shooting it sooner, when I didn’t like the resistance.

I gave them both equal effort but feel that the defiance setup and trigger had a real advantage. The 40X had the bands manipulated and supplemented right before shooting and the McMillan stock, not barreled action, was shot for its first time when zeroing the scope, so that settling in was about even also.

I don’t know if someone has that program app to measure these, bit I will do later with calipers if not.



I feel like the banded gun wants to shoot tighter, probably did, but that off the same gear it would have been clearer. The trigger cannot be pulled without counter pressure on the old fashioned grip, or else the gun will really move. The Jewel will fire with or without using the grip.

Sequence of shots was left to right as before.

 

[Brians356]

There was a .22 match going on until the afternoon, where is was 102 ...

But it's a dry heat.
-

 

[davidjoe]

Rough caliper test put the groups as follows, with the banded rifle having a larger sample size. I may tend to measure them optimistically, but if so it is pretty uniformly done that way.




Because of the ammo challenges today it’s worth repeating in good conditions with lower pressure ammo. I suppose though that one of the main potential benefits of a strapped gun is that it’s going to constrain adverse conditions affecting barrel movements into a “smaller box”.

The banded gun’s groups were 81.5% as large as the free floated rifle.

 

[davidjoe]

I found a nice old low pressure load of the discontinued 105 scenar moly bullets, with plans to come out to the range and one hole punch some Sharpie lines to prove my ugly stick works, and this happens on the fourth shot. Never had this before.






I imagine this is going to be hard to remove at home. Any suggestions. (I can see stress and fissure lines at the same place of the loaded round).