Gunsmithing 6.5x47 Reamers - Why such tight necks?

[Campguy308]

I have always been intrigued by the 6.5x47 Lapua round, at least from reading on the internet. However, I've had 2 barrels that did not perform like they should (completely piss poor). In the attempt to troubleshoot these problems, I discovered that what many people call a "no-turn" neck, may not actually be a true "no-turn" neck.

Both of the barrels that I've had chambered, with two different reamers, a Manson and a JGS, have a .292 neck dimension. A loaded Lapua round measures right at .290. This only leaves .001 per side. I do not believe this is sufficient for a field rifle, and has led me to start turning necks for the .292 chamber.

When I look at reamer prints for other 6.5 rounds (6.5 Creed and 260 Rem), I see most of them have at least a .297 neck dimension. The largest X47 reamer neck dimension that I have found is .295, with most of them being .292.

I know the X47 has it's roots in the BR/F-Class world, but it is frustrating to know that most "no-turn" X47 reamers on the shelf are so tight in the neck area as compared to the other 6.5mm offerings.

I am considering chambering another X47 barrel, but I want to get away from the neck turning/tight neck dimension, and would prefer to find an off the shelf reamer, just like is readily available for the other 6.5mm rounds.

What are your thoughts on this?

 

[natdscott]

Call JGS, get their prints, and have them make one for you how you want.

 

[pyplynr]

I have 2 - 6.5x47 rifles and have never turned any necks. Both shoot amazing. Both were built by Jon Beanland. I don’t know what reamer was used, but I’ve never had any problems out of either.

 

[Campguy308]

I have 2 - 6.5x47 rifles and have never turned any necks. Both shoot amazing. Both were built by Jon Beanland. I don’t know what reamer was used, but I’ve never had any problems out of either.

I emailed him a while back. He uses either a .294 or a .295 neck, can't remember which. I have heard nothing but excellent things about his X47 builds.

 

[Supersubes]

In perusing various 47 reamers, I’ve found most of them to be pretty good. Probably due to the single source great brass, and dedicated use in bolt action match/precision rifles.

My reamer has a .295 neck, and works great. I still have my original brass from 2008, and it’s been used in three barrels so far. Well north of 20 firings.

Do you own these reamers, or those are just the reamers used by the smiths who chambered your barrels? If you do own them, and you’re happy with the body dimensions(not neck), consider buying a neck reamer, or a neck throat combo reamer for $100 with a .295 diameter.

 

[Campguy308]

I don't own the reamers. They are what 2 different smiths had at the time. Which reamer do you have? Or is it a custom? It seems like .295 is the way to go, leaving about 2.5 thou per side of clearance.

 

[biffj]

I have a local smith friend that has built over 300 Rem 700 rifles in 6.5X47 using a Manson no turn reamer. Not sure of dimensions but I know it was ordered as the no turn version. He also reamed the chamber of the barrel for my Desert Tactical rifle. In all that time there have been 2 barrels that didn't shoot right. One turned out to be the wrong twist rate and the other was a too tight bore. In truth the too tight barrel was really accurate but showed pressure signs before reaching the desired velocity so the customer wanted it replaced. Both were replaced by the barrel maker. The rest have all been excellent shooters. I'll get some info from him on the neck diameter but whatever it is it seems to work just fine.

Frank

 

[Campguy308]

I have a local smith friend that has built over 300 Rem 700 rifles in 6.5X47 using a Manson no turn reamer. Not sure of dimensions but I know it was ordered as the no turn version. He also reamed the chamber of the barrel for my Desert Tactical rifle. In all that time there have been 2 barrels that didn't shoot right. One turned out to be the wrong twist rate and the other was a too tight bore. In truth the too tight barrel was really accurate but showed pressure signs before reaching the desired velocity so the customer wanted it replaced. Both were replaced by the barrel maker. The rest have all been excellent shooters. I'll get some info from him on the neck diameter but whatever it is it seems to work just fine.

Frank

Thank you. My current X47 barrel was chambered with a JGS CIP reamer. Not sure if it's advertised as no-turn, but it's a .292 neck. The first barrel was a Manson with a .292 neck.

I have a couple friends that shoot 6x47. They both had major accuracy problems until they started turning necks. The reamer was advertised as a no-turn. They seem to believe that you need more than .001 per side of clearance to eliminate this.

 

[padom]

Ive had easily 12+ 6.5x47L barrels chambered by 3 different smiths and never had a single issue with any of them. All super accurate and run great.

 

[Campguy308]

The feedback that I'm seeing here aligns with what the rest of the internet says about the cartridge, hence the reason I'm interested in it.

If I chamber another one, it'll be with at least a .295 neck. That's still tighter than most 6.5 Creed and 260 reamers. Not sure if that means anything, but I think it's worth noting.

 

[natdscott]

Here's this, to simplify, and remove the internet. Some of this you obviously know, but I type for all the interneters, not just you.

Fact: For now, it's proprietary, and Lapua is very (very) good at controlling brass from lot-to-lot.

1) If you have brass, measure the neck thickness.
2) Add that thickness x2 to the bullet diameter of 0.2645".
3) For Benchrest, add 0.003-0.004" to the dimension for your needed chamber neck (if you don't want to turn)
3b) For most other stuff, add 0.004-0.006", depending on how clean you want to be.

When you fire your brass, and gently eject it, you should see a carbon pattern around the neck that is wavy, and ideally, with some of it carbon-coated all the way to the neck-shoulder junction. If it is a round ring up near the front, you almost certainly do NOT have enough neck clearance.

Sacred cow trigger warning.

Same as neck-only sizing, the theory and belief that tight-necking chambers leads to greater accuracy has been pretty darn well debunked by the best shooters in the world, at almost any range from 100y SRBR through ELR distances. With the noted exception of the traditionally-chambered belted mag, rifle rounds need to have good clearance to be able to self-center on the SHOULDER of the casing/chamber at ignition. Some think the neck can be used to help...the best don't seem to agree.

0.292" is WAY too damn tight for a 0.290" round. WAY. 0.001" of carbon on the bottom of your neck (which does not compress well) can put you into tight territory, as far as cartridge alignment...hell, I can imagine a 0.001" difference.

So don't.

You're on the right track...just get JGS to make/sell you one with a little more material left on the neck. They'll be happy to take your money.

 

[30338]

I've got a PTG reamer 813194. It has worked well for me using 140 to 147 bullets. No issues with neck being tight in chamber.

 

[Supersubes]

I don't own the reamers. They are what 2 different smiths had at the time. Which reamer do you have? Or is it a custom? It seems like .295 is the way to go, leaving about 2.5 thou per side of clearance.

Mine was the standard offering from ptg at the time. It hadn’t been out too long, and hadn’t been screwed with much. I can give you a print number later. .295 is perfect. As someone else mentioned, there’s absolutely zero reasons to do tight neck anything. Causes issues and solves none imo.

 

[Campguy308]

Mine was the standard offering from ptg at the time. It hadn’t been out too long, and hadn’t been screwed with much. I can give you a print number later. .295 is perfect. As someone else mentioned, there’s absolutely zero reasons to do tight neck anything. Causes issues and solves none imo.

Thanks for the info. The standard JGS and Manson offerings appear to be .292. I believe I will seek a .295 on the next spin up. I do not understand why these tight neck reamers are so common.

 

[Campguy308]

Ive had easily 12+ 6.5x47L barrels chambered by 3 different smiths and never had a single issue with any of them. All super accurate and run great.

Do you know what reamers were used?

 

[Supersubes]

Thanks for the info. The standard JGS and Manson offerings appear to be .292. I believe I will seek a .295 on the next spin up. I do not understand why these tight neck reamers are so common.

It’s funny, I was just searching them and you’re right, they’re tight mostly. Grizzly industrial(which stocks ptg) has their version on sale for 149. It’s a .2944 neck, .167 freebore. From memory the rest of the body dimensions look standard.

It’s good you’re sticking with it, as it’s a real peach of a cartridge. Why not just buy your own reamer, then never worry again? JGS or Manson will send you everything they have on it if you ask. If you have more questions, post the ones you think are right to this thread and let the peanut gallery give you the yay or nay.

 

[ram]

I’m having a barrel chambered at GA Precision, and there reamer print has a 0.293” neck. Is this too tight without neck turning?

 

[Campguy308]

I’m having a barrel chambered at GA Precision, and there reamer print has a 0.293” neck. Is this too tight without neck turning?

Who makes the reamer? Is the .293 dimension at the case mouth, or near the neck shoulder junction?

 

[Supersubes]

I’m having a barrel chambered at GA Precision, and there reamer print has a 0.293” neck. Is this too tight without neck turning?

You’ll have clearance, but it’ll be minimal.

 

[Campguy308]

Some of these reamers have a .293ish dimension at the neck/shoulder junction, tapered down to a .292 at the mouth. Which is a .292 neck, not a .293ish neck.

 

[ram]

Who makes the reamer? Is the .293 dimension at the case mouth, or near the neck shoulder junction?

PTG. 0.293 at the case mouth and neck shoulder

 

[Sig Marine]

Some of these reamers have a .293ish dimension at the neck/shoulder junction, tapered down to a .292 at the mouth. Which is a .292 neck, not a .293ish neck.
View attachment 7072182

I have a rifle chambered with the exact reamer you show and it is a hammer. I've had absolutely NO problems with extraction. To the OP, one thing to remember: a larger neck means working the brass more when sizing down for neck tension. I'm using a .288 bushing to get .002 neck tension. YMMV

 

[natdscott]

Benzomatic.

 

[Edds]

Some of these reamers have a .293ish dimension at the neck/shoulder junction, tapered down to a .292 at the mouth. Which is a .292 neck, not a .293ish neck.
View attachment 7072182

JGS will make that reamer for you and change the neck diameter to anything you want.

 

[Campguy308]

I have a rifle chambered with the exact reamer you show and it is a hammer. I've had absolutely NO problems with extraction. To the OP, one thing to remember: a larger neck means working the brass more when sizing down for neck tension. I'm using a .288 bushing to get .002 neck tension. YMMV

If it is a hammer, that is all you need to worry about. I do have a question. After you fire a round, can you drop a bullet into the fired case neck? If you size your fired case with a .288 bushing, does it take out any out-of-roundness in the case mouth?

Over working brass is not a good thing, but I believe it to be better than too tight a neck.

I still question why x47 reamers are so tight in comparison to 6.5 Creed and 260 dimensions.

 

[Supersubes]

If it is a hammer, that is all you need to worry about. I do have a question. After you fire a round, can you drop a bullet into the fired case neck? If you size your fired case with a .288 bushing, does it take out any out-of-roundness in the case mouth?

Over working brass is not a good thing, but I believe it to be better than too tight a neck.

I still question why x47 reamers are so tight in comparison to 6.5 Creed and 260 dimensions.

In the dimensions we’re talking about, overworking brass is a non-issue.

I looked at my print. PTG print number 18124. It’s dated 6/09. Body dimensions are identical to the grizzly PTG reamer I mentioned above, but my neck is .295 vs their .2944. Their’s also has .167 freebore vs my .123, so it would be better suited for 140 gr bullets.

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[Campguy308]

When you fire your brass, and gently eject it, you should see a carbon pattern around the neck that is wavy, and ideally, with some of it carbon-coated all the way to the neck-shoulder junction. If it is a round ring up near the front, you almost certainly do NOT have enough neck clearance.

When I shoot unturned brass in the .292 chamber, the cases come out clean as a whistle, no carbon on neck. A bullet will not drop into the fired case, and could actually have a bullet seated again without any sizing done.

My last barrel chambered with the .292 built up a carbon ring in the throat that was unlike anything I have ever seen. I scrubbed for 3 days with every chemical known to man, and could not get it out. It was gouging the bullets when I'd chamber a round. I ultimately pulled that barrel for that reason.

I don't know if that had anything at all to do with the neck dimension, but the whole carbon ring situation, combined with the tight neck issue, and a poor shooting barrel was very frustrating.

 

[natdscott]

When I shoot unturned brass in the .292 chamber, the cases come out clean as a whistle, no carbon on neck. A bullet will not drop into the fired case, and could actually have a bullet seated again without any sizing done.

My last barrel chambered with the .292 built up a carbon ring in the throat that was unlike anything I have ever seen. I scrubbed for 3 days with every chemical known to man, and could not get it out. It was gouging the bullets when I'd chamber a round. I ultimately pulled that barrel for that reason.

I don't know if that had anything at all to do with the neck dimension, but the whole carbon ring situation, combined with the tight neck issue, and a poor shooting barrel was very frustrating.

Yuppers. 100% sure that's a neck that's way too tight. Did you blow primers, or see other pressure signs?

That's the sort of condition SOME BR guys try, and/or tried. Thing is, you're not trying for that, are presumably not turning, and you don't want to be shooting BR with only 25 casings that are good-to-go, and load them at the line with many incantations and much consternation....

You won't always see pressure, as long as you're right ON the edge...but it just doesn't take much to make those loads 75,000 psi instead of 59,000. Not necessarily a safety concern, but does nothing good for accuracy, case life, etc. The carbon ring pre-engraving your bullets is shit though.

I can't speak to WHY the ring would have formed worse in that barrel, but I do know the neck thing.

Do you turn?

Try this, next time you're getting real persnickety: with a "normal" load in a casing a little too tight, start turning the necks down 0.0005" or so at a time, until you JUST get that wave effect on the necks of your brass. When you get there, measure that thickness, and your loaded round, and you already know your chamber, you'll know the ideal clearance.

I betcha it's not 0.001".

As you move along shooting and loading a known load, if you WEREN'T, and then you start getting casings coming out with pressure, concentric soot, or certainly not passing the bullet drop test, and/or accuracy going to shit, then you just about certainly have a ring in the chamber.

 

[Campguy308]

I am turning now, because I have since learned more about neck clearance. I am turning to .286, and using a .283 bushing. This leaves me with .003 clearance per side.

However, I am not having much success with this newest barrel, turned or not. Not sure the reason just yet, but if I chamber another one, I will be getting a reamer with a minimum .295 neck. Turning sucks, and I never want to have to do it again.

I never noticed any pressure signs from loads that weren't near the top end.

Here is a pic of the gouge from the carbon ring in the last barrel:

 

[natdscott]

Is that completely around the bullet?

If your freebore is tight, you CAN get those from a bullet out of concentricity...though that's quite a bit.

But yeah, turning isn't the best most funnest.

 

[Campguy308]

Not all the way around, but almost. I cleaned it until that went away, but it came back after 20 rounds fired.