A somewhat different contour question...

[ShootMo]

Thank you JE. I guess in all of my reading and research about barrels lately, that I got a little singularly minded.

 

[nathank]

you could add a NV hood from MDT and it would cover the barrel channel

 

[nathank]

someone skilled with a 3D printer could probably print a nice cover that could bolt up to it and look real clean

 

[epoletna]

Shoot Mo:

I have cast barrel channels that were very close to the barrel couture by putting a couple thickness (or more) of box sealing tape on the barrel, coating that with release agent (two layers of shoe polish, then some light oil) and pressing it into the epoxy resin. When you remove the tape you'll have a gap of about 1/16". Add more layers of tape if you want a larger gap.

 

[freddiej]

JE said it before I could. put me down for saying the same advice as JE.

 

[ntsqd]

Believe it or not, MDT says zero bedding.



Thank you for the response. I can't really see why it could be detrimental to contour it like I'm thinking from a physics standpoint. But I don't know diddly about barrel science. Lots left for me to learn.

Hum, well I can tell you that the MDT chassis that I've got for a Howa Mini doesn't fit tight to the sides of the action at all. No guaranty that it will repeat location every time that I remove & replace the action. I've already started the prep to bed it using Devcon AL putty. I do not expect there to be much under the action, but there will be considerable bedding compound on the sides.

This particular action presents a unique machining challenge in that the front action screw threads into the bottom of the recoil lug, and the action is flat bottomed. Mr. Murphy says that the dim between those two parallel surfaces will have a tolerance; and that the dim between the two mating surfaces in the chassis will also have a tolerance. I am expecting the bedding to 'adjust' the stack of those tolerances to be zero.

 

[ShootMo]

That's a cool idea. I'd love to learn 3D printing. I don't know of anybody who has one or does it, personally.

 

[ShootMo]

Hum, well I can tell you that the MDT chassis that I've got for a Howa Mini doesn't fit tight to the sides of the action at all. No guaranty that it will repeat location every time that I remove & replace the action. I've already started the prep to bed it using Devcon AL putty. I do not expect there to be much under the action, but there will be considerable bedding compound on the sides.

This particular action presents a unique machining challenge in that the front action screw threads into the bottom of the recoil lug, and the action is flat bottomed. Mr. Murphy says that the dim between those two parallel surfaces will have a tolerance; and that the dim between the two mating surfaces in the chassis will also have a tolerance. I am expecting the bedding to 'adjust' the stack of those tolerances to be zero.

I'll likely bed this one too even if it will only be skim-thickness. I'm going to sort out this barrel quandry first though.

 

[Bart B]

Any given barrel contour will vibrate, whip and wiggle the same resonant and harmonic frequencies for every shot fired. How much is determined by cartridge size. 32" long skinny barrels are just as accurate as a fat one of the same length even they vibrate at different frequencies. Tune your load so bullets leave at the right place in the muzzle whip.

Any contact on the barrel by the fore end transfers a force point to the barrel that changes how much and what direction the barrel vibrates. All forends bend from the rifles own weight and other external forces caused by what holds it.

No bedding under the chamber area.

 

[ShootMo]

Shoot Mo:

I have cast barrel channels that were very close to the barrel couture by putting a couple thickness (or more) of box sealing tape on the barrel, coating that with release agent (two layers of shoe polish, then some light oil) and pressing it into the epoxy resin. When you remove the tape you'll have a gap of about 1/16". Add more layers of tape if you want a larger gap.

Y'all are some pretty bright lightbulbs. That might just be exactly what I do.

 

[Savage 12BVSS]

My smith had to fill my barrel channel back in when I went from varmint profile back to a medium sporter profile. It looked foolish in the big channel but the stock was not gonna go so he filled it in and sanded and I repainted it to match the stock color. You can't tell now and the gun lost a lot of weight going smaller contour and shorter new barrel. I don't know what he used (probably what he beds with) but it was workable and looks great.

 

[J E Custom]

Hum, well I can tell you that the MDT chassis that I've got for a Howa Mini doesn't fit tight to the sides of the action at all. No guaranty that it will repeat location every time that I remove & replace the action. I've already started the prep to bed it using Devcon AL putty. I do not expect there to be much under the action, but there will be considerable bedding compound on the sides.

This particular action presents a unique machining challenge in that the front action screw threads into the bottom of the recoil lug, and the action is flat bottomed. Mr. Murphy says that the dim between those two parallel surfaces will have a tolerance; and that the dim between the two mating surfaces in the chassis will also have a tolerance. I am expecting the bedding to 'adjust' the stack of those tolerances to be zero.

No machined chassis will be an exact fit because the actions themselves are not machined exactly the same as others from the same model and company.

Some of the chassis are very close and some are not depending on their quality control and the action makers quality control.

A good bedding job will make it a perfect fit and It will not just "Drop" in. I prefer to use a chassis system in any stock material because it gives me a good foundation for the bedding. Pillars do the same thing on compressible materials.

Any chassis system is good, but normally more expensive than one without. But bedding any of them correctly will produce more consistent fit when removing and replacing the barreled action . As with anything there are always a downside to anything but these can be addressed an dealt with.

So I recommend properly bedding everything for best fit and function.

Just my opinion

J E CUSTOM

 

[ntsqd]

I am treating the areas immediately around the action screw holes as "pillars" and bedding the rest as would be normal for a wood or composite stock. Including using a carbide burr to rough up the, in this case, aluminum, and remove most of the cerakote to promote better adhesion. Already bedded the EGW 20 MOA rail as it did not fit the action correctly.

I specified the barrel contour that I wanted with a CAD drawing and Satern built it to the drawing. Right or wrong it has a short Ø1.150" cylinder over the chamber tapering to a Ø0.750" muzzle over a 24" length. The barrel channel in the chassis looks like it was designed to clear a Ø1.25" cylindrical barrel, so there is some considerable gap. Particularly at the forearm tip. I'm OK with that, I just wish that the forearm itself was a bit stiffer. I can slightly warp it while twisting it with a gorilla grip.