Hot Barrel and Accuracy

[David Milisock]

My thinking as well. If I can't get it done in 3 shots I don't need to be out there in the first place.

I like old rifles, of course they weren't as old as they are now when I got them.

They are all cold bore zeroed, and some hold great two shot placement all have good 3 shot placement.

In the field I don't recall shooting any of them more than once. The great part is that some of them I got for under $100 bucks one was $175 but that was an already finished sporterized 8MM JS Mauser.

My 6.5x55 Swede I paid $85 for, cut the front sight off, mounted a scope, an aftermarket trigger and got a synthetic stock.

 

[MUP]

I like old rifles, of course they weren't as old as they are now when I got them.

They are all cold bore zeroed, and some hold great two shot placement all have good 3 shot placement.

In the field I don't recall shooting any of them more than once. The great part is that some of them I got for under $100 bucks one was $175 but that was an already finished sporterized 8MM JS Mauser.

My 6.5x55 Swede I paid $85 for, cut the front sight off, mounted a scope, an aftermarket trigger and got a synthetic stock.

Speaking of price, IIRC I paid $200 for that Model 70 as well. And it came with a Simmons 10x scope mounted even.

 

[davidjoe]

As you move from a bar of steel to a strip of steel, the warping and curling when heated become severe. It’s so predictable that there are science experiments in lab class to demonstrate it. The opposite direction of a thin strip is a solid block or ball of steel that will barely change its shape at all when heated. Between a 3’x3’x3’ block of steel with a rifled hole in it, and a thin barrel, is the thickest barrel you can get away with in an application.

Free-floating a 1.25” barrel with a ~1 inch tenon in a 1.35” receiver that is say 32 inches long is putting a lot of stress on that junction in my opinion. If you think you have strong hands, try holding such a barrel parallel to ground, by the tenon.

Undoubtedly the longest mass-produced barrels in the world are free floated, - triple gun naval cannons, however, these are thin for their length, short for their caliber, and don’t come anywhere close to the proportions of a 1 inch tenon on a straight taper target barrel. I believe the counterpart to their “tenon” is massive relative to a target rifle.

If there is going to be a rigid stock extending the length of the barrel, anyway, why not utilize it skillfully for support and vibration control? We have all seen Vulcan 6 barrel Gatling style cannons. It would be incomprehensible, ludicrous even, for them not to be connected to each other for mutual support, out near their muzzles. If we saw six cannon barrels not secured inside that “ring”, it doesn’t matter whether one is a florist, pharmacist or firearm manufacturer, everyone would agree that wasting that potential connection is a very bad idea.

 

[David Milisock]

Speaking of price, IIRC I paid $200 for that Model 70 as well. And it came with a Simmons 10x scope mounted even.

Lots of fun for little money. I bought some of mine just for the actions and realized with a little work I had acgreat shooter.

I do believe all mine were good examples of the thin barrel and pressure point concept.

 

[gunsandgunsmithing]

Strictly from a harmonics standpoint, the heat we induce with and over ambient is not a lot in the big picture and has some but very little effect on frequency. Two things happen. One is as the bbl heats, the molecules are further apart and less dense. The other is that because of this, it actually grows a tiny amount. Change above ambient is what we are talking about here and it's just not much. There are online calculators that will tell you how much the bbl grows. Without looking it up, lets call it about .002" in length over a 30° temp change. Again, not much. Also, the frequency does change a bit. It can be seen by ringing a tuning fork, fresh out of a freezer vs letting it come up to ambient temp.
But with those things said, even combined, the effects get lost in the noise. The biggest factor is powder. It turning from a solid to a gas is a chemical reaction and all chemical reactions are temperature dependent. Some powders are better than others, but all gain speed with heat. So, we have bullet exit time happening sooner at a higher temp than a cooler one. This far overrides the lengthening of the bbl due to heat. The effects of everything combined still leaves us working within a single wave form at the frequencies we are dealing with and the very short in bore times of the bullet. So what we are changing with a tuner, for example, isn't so much frequency as it is phase time. We are literally shifting the top of a single sine wave left or right and timing that with bullet exit. Powder charge, seating depth and neck tension are all doing effectively the same but the other way around. By changing a load a few tenths, we are still within a single wave form and speeding slowing the bullet to exit while the bbl is at the best place for accuracy. IME, I prefer that to be at the top of this sine wave. You can see this by either method as poi changes slightly and groups get bigger or smaller.
I believe you your friend is wrong about the whip of the bbl as I interpret how you put it but he's on the right track I think.

 

[Rat Rifle]

Last year I attended a match with the late Stan Taylor, of Douglas Barrels. Regrettably, we lost Stan a few months back. After the match, sitting around with a cold beverage, talking guns, Stan said that a REM 700 action, and I assume a Savage or any other factory 1.350” action, could only effectively support a 1.250” barrel out to 24”. After that, there was too much weight on the tendon. Stan barreled a lot of actions. I’m confident He knew what He was talking about. Rest In Peace, Stanley old Friend.

 

[K22]

After 55 years of shooting I'm interested in the results more than what it takes to achieve them. As I said I have 1 varmint free floated and one not floated both shoot well.

I will agree that the stock bedding is important however I'm not qualified to claim that a good stock and bedding is all that's required to use a free floated barrel. I have a 102 year old Remington Model 17 that was sporterized that shot poorly. I relieved some stress points in the stock and that helped but not enough. I then added a pressure point and now it shoots 3" at 300 yards, not bad for an old WW1 battle rifle.

I think McGowan bedded my 358 because he said a 1.2" diameter (no taper) 30" barrel would sag over time and stress the receiver. At the time and now I am not at a point with my mechanical knowledge to argue, especially given the fact that having a 358 Norma Magnum that pushes a 250 grain Hornady SP at 3,200 FPS and averages 1 1/16" groups has proven the man right with this one.

Don't ask why that type of barrel, suffice that 600 yard cold bore shots work fine, I sent along 3 dummy rounds to cut the throat and to test feeding.

Mike Burns built me a custom dangerous game rifle in 450 Marlin on a Mauser 98 with a 22" Shilen air guage medium weight barrel that is also bedded. Accuracy is awesome for this type of rifle but a 500 grain projectile at 2,000 FPS is unhealthy as a bench rest rifle.

Couldn't agree more - my focus is on performance, not the theories or technicalities. I leave that stuff to my rifle smith. If the rifle performs to my standards - how he got there I really don't care. I was merely communicating his opinions on bedding, floating, etc.

That performance philosophy also applies to reloading, cleaning, etc. for me.

 

[K22]

I haven't seen a Tikka not shoot. My CTR from 2017 was a hammer. The last Lite .308 I had (and regretfully sold) was a solid 1/2 MOA factory rifle with handloads. I'm probably going to pick up another.

My 308 Hunter (lite version with a wooded stock) shot very well but the recoil was brutal off the bench with full power 150 and / or 165 grain bullets. Even off the shooting sticks it was no fun to shoot at all. So, I went to a reduce loading with 125 grain bullets and H4895.

Perhaps because I'm an old guy with a light frame I was more sensitive to the recoil. Of course, when you're hunting, you'll never feel the recoil, but I like to shoot a lot at the range. For me, when the caliber gets above 243 in the Tikka Lite's, it isn't fun to shoot at the range.

 

[drop_point]

My 308 Hunter (lite version with a wooded stock) shot very well but the recoil was brutal off the bench with full power 150 and / or 165 grain bullets. Even off the shooting sticks it was no fun to shoot at all. So, I went to a reduce loading with 125 grain bullets and H4895.

Perhaps because I'm an old guy with a light frame I was more sensitive to the recoil. Of course, when you're hunting, you'll never feel the recoil, but I like to shoot a lot at the range. For me, when the caliber gets above 243 in the Tikka Lite's, it isn't fun to shoot at the range.

Personally I’ve not had any problems with the .308 version. When I got mine I was 170 lbs or so and 6’. I’ve gained a bit of weight since then, and while not a problem initially, it was more comfortable after adding a little padding. My kids are probably going to start our on a 6.5 Creedmoor though.

 

[Tesoro]

Like to add a thought after reading the post above about the fellow not being able to thread hot well pipes.
I have a Sauer M200 in 30-06. The barrel and receiver lugs are one and the same. The bolt locks into the barrel so the receiver is nothing but a bolt guide. It is a floating slide in switch barrel and the forearm is not part of the butt.
This rifle will shoot sub moa and maintain poa cold, warm, hot or smoking hot. Dosen't make a significant difference.
This makes me wonder if the barrel to receiver threading might be an under looked cause of inaccuracy when excessive heat is added to the accuracy formula.
I have shot 5x .25moa with rifle off bags in consecutive shots with no cool down in between shots or strings.