JR FIREARMS

Seen a few Sabattis lately where the picatinny rail screws have stripped out the action under recoil. I have found various causes for this which ultimately are all down to quality issues. It’s a fairly simple fix, especially with the CNC mill. It’s a case of measuring hole spacing, a quick CAD model, then boring out and threading for larger threads, In this case 8-40. The rail also needs machining to allow fitment of the larger screws.

Yes i’ll make a note to check of some i have. Weight saving is usually minimal.

Hi Chaz, i’m unable to PM you for sime reason. Email me or text me on info@jrfirearms.co.uk or 07801432618

It’s quite a beast, 1.25” down to just over 1” at the muzzle.

Spiral fluting on this very heavy 30” barrel.

Been a bit busy of late getting rebarrels/builds off to proof by christmas. Here are a quick couple shots. IMG_0944.mov

Some may consider this a waste of time but it’s quite popular. It’s a tactical bolt conversion for RH Tikka T3/T3X’s. Obviously you can buy replacements that are normally a DIY fit, but some customers don’t like the straight aftermarket handles, or the fact they are usually a bit too long and spindly. And occasionally are a poor fit. I modify the original handle to accept one of my in-house made bolt knobs, and turn it to have a smooth transition. The end result is an improved handle with an OE look. It’s a bit more work but many customers prefer it, and i feel it looks a little nicer and unique.

First time i’ve heard that cold forging doesn’t induce stress and cut rifling does. It would be interesting to know if they apply any more inspection to fluted versions. We also know Remington barrels are hit and miss in terms or accuracy, quality etc. I see a fair few where people have issues getting on target etc. It’s not always scope base issues. As previously stated, i never said they can’t be done. Just mearly i personally won’t and it’s generally not recommended. This is based off of real world experience from my own tests and other. And i’m pretty sure i’m not the only UK rifle builder to say he same. It’s all interesting stuff though 🙂

It’s always nice to share opinions and experiences.

Button rifling will of course induce stress, but not as much as cold hammer forging, that’s what i more referring to 🙂. Once button barrels are stress relieved correctly very little stress remains that will be of any major concern. Where as hammer forged will always have stresses remaining, and often bad enough to cause issues.

It may well be one of the reasons. Obviously it can be done, but we’ll never know how many get rejected or what process they follow. Or just not bother checking and let it ship. It’s not uncommon to hear of people with factory rifles that don’t shoot, or can’t get the shot on paper as they run out of adjustment etc.

😂 very true. The money would be better spent on a new barrel or bolt fluting 😎 I’ve always read/hears about varying degrees of factory barrels stress relieving, and witnessed it with small muzzle threads on large bore calibres. But it was interesting to see first hand just how badly it can happen! Had this old Rem barrel been a customers rifle, it would be ruined. Unless there is a new competition that involves shooting round corners 🤣

Nearly all factory barrels are hammer forged, this induces stresses into the steel. When you machine the barrel with something like fluting or re-profiling, those stresses can release. This can cause swelling in the bore diameter or physical bending/warping of the barrel. This may not always cause accuracy issues, but you can get other issues such as running out of scope adjustment because the barrel is trying to shoot round a corner. Custom barrels are normally either cut rifled or button rifled, this imparts little to no stress in the steel. They also tend to undergo better heat treatment processes to relieve stresses in the steel. So when you profile or flute them the chance or causing issues is virtually zero.

Agreed that a curve in the bore is quite common and not likely to cause issues if chambered correctly. But this barrel physically bowed/bent as a result of removing material. So you would be unlikely to get the shots on target at distance, you’d run out of scope adjustment. Tikkas/Sakos may be better than others, but I personally don’t see why anyone would risk ruining a rifle for the sake of it.

Yes you may get away fluting 99% of factory barrels, but why risk ruining a customers barrel for the sake of profit. The first barrel in the pictures suffered severe stress relieving, and is a perfect example of why not to do it. Although it would now be handy for shooting round corners 😂 Although any material could stress relieve, custom barrels undergo a special heat treatment and stress relieving process. Combine this with the much less stressful machining process of button or cut rifling, it is highly unlikely to happen. If it was of any potential concern then the barrel manufacturers wouldn’t offer fluting themselves. But it is important not to flute too deep.

Yes that is juts a practice piece, which also developed a 1mm bow in the middle due to stress relieving. Had that been a customers barrel it would now be scrap.

I’ll only flute custom barrels, no factory barrels. They have a tendency to warp.

A little more testing done. Tool paths are all good, i just want to enhance the tool holding and support.

The more i see it the more i like it.

Yes it’s much nicer to make it a true fit. It’s more stable and looks better.

Here is mock up of the interrupted fluting pattern.

I’m not personally a fan of the Blaser fluting and it has never been requested. But my current programs easily allow an increase in the flute quantity to have a similar look, but it wouldn’t flow into the swamp like the blaser. This would require a more complex and custom program for each barrel, and it would make it quite costly.

https://youtu.be/4x74Np-_zYo Quick video of the fluting in action.

Finally had chance to set the machine up for barrel fluting and test the new programs i’ve written. Straight and spiral will be offered, and interupted at some point later one (it’s alot harder to write the program). There are a few bugs to iron out and most testing, but so far so good

One of the nice things about having access to a CMM (coordinate measuring machine), it allows you to measure profiles/shapes very accurately. This was only a quick simple job of attaching a small picatinny rail to a stock forend, but the tight radius meant the rail wouldn’t sit flat or securely. So having measured the stock and then replicated the profile in my CAD software, i was able to 3D machine/profile the bottom of the rail for a true 1 to 1 fit. I’ve used a similar process to make custom stock spacers that had fixed length of pull.