Just picked up a SS Model 7 in 7-08 for my son. Bore scope shows that the start of the lead looks crooked. A couple lands are longer than the others. I'll see how it shoots first, but if it does not perform to expectation, do I have enough shank to set back the length of the neck (~.250")? Thought would be to center up the bore and taper bore the chamber under-size to concentric and then finish ream.

I'll have a section in the middle of the shank that won't have a thread if there is a relief groove. Just spit-balling at this point. I have a coupele extra .308 barrels but I like the 7mm version.

What is the OD of your barrel where you want to extend the shank to? Thread OD is 1.0625. Subtract that and you will see if there is any shoulder left. Doesn't take much.

quote:

(~.250")?

What would that be 4.5 turns? Sure would look like crap in the barrel channel.

I would get a new barrel before I set it back that far.

First issue will be how does it shoot.

The reason the leade is not even is because the chamber is not in line with the bore. It's my understanding that Remington uses pilotless Reamers to cut chambers, and if they don't go on straight you get a crooked leade; I've seen it before. Good luck with it.

Cleaning up the old Remington 308 chambers is simple. There is no relief cut on the threads so the old thread can be picked up with no problems. You have to shorten the shank by exactly 3 turns or .186 inch and cut the shoulder and bolt nose recess forward the same amount and recut the chamber. This generally recuts the entire throat and case neck plus the .018 inch extra which is built into the neck of the chamber for over length safety. This conversion used to be quite popular back in the day when we were tight-necking and shortening the ridiculous 1 caliber of throat which came as standard in the factory 40XBs and Remington Varmint Specials. I won't say I've done hundreds of these but enough that they once became a bit of a bore. Done correctly, you can't even tell that some one has dicked with it. The inletting is still generally very close and at the most you may lose part of the magnuflux mark △ and an assemblers stamp. Some times not even that.

Shoot it and maybe nothing needs to be done.

+1 with Rod.

Remington uses pilotless reamers? Is that true? If so, I can't fathom it.

I think he's referring to solid pilot reamers as opposed to live pilot reamers.

No, not solid pilot. Guy Malmborg told me about Remington using pilotless reamers. Think about it, how could the leade be cut uneven any other way?

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Originally posted by dpcd:
Remington uses pilotless reamers? Is that true? If so, I can't fathom it.

I have heard this terminology used over the years Tom. I can't say if the reamers are actually (pilotless). I generally took it to mean that they were (solid pilot). There is such a thing as pilotless reamers though. I have had a few over the years. They were made by Hartford Tool and Die and were caliber stamped and marked (SIZE). They were undersized reamers used for making resizing dies and they ended basically at the end of the neck with a 60 degree taper of about .100. As far as Remingtons chamber reamers being totaly pilotless, I can't see what advantage it would offer them and I can see it creating nothing but problems.

I have seen a few of the off center throats that people always describe. Closer inspection usually shows that it's actually a difference in the depth of the grooves that is actually the cause and it gives the appearance of it being off center. I once cornered old Grandpa Ron Smith and asked him about it. If memory serves his replay was something to the nature of (damned reamer cut oversized and the button or cutter got cockeyed). I also asked Rudy VanOwen about it and his answer was roughly the same with the added quip about hammer forging belonged on horse shoes. Rudy hated cut and broach rifled barrels a lot, but he REALLY HATED hammer forged barrels.

The barrels I've seen this phenom on had evenly cut lands and grooves, but I can certainly see how lands of varying height could appear similar.

If people provided photos these things could generally be sorted out a lot easier.

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Originally posted by speerchucker30x378:
If people provided photos these things could generally be sorted out a lot easier.

Ask and Ye shall receive.
Compilation pic below of most of the lands. The dark area on the right is the end of the neck, beginning of the throat. You can see as the pics progress that the lands are wiped out as you go around the bore. At #4 the land is starting about 3/4 of the way to the left. I think I left two lands out that were wiped out. Lands are all centered vertically. Hard to say how far down the bore it extends but if the lands are .004" tall, the chamber is offset or crooked about that much.

Just like the ones I've seen. Metal that would've been the bottom of a groove is removed on one side while lands opposite are barely touched. How you going to do that with a piloted reamer?

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It's sort of hard to say. It could be a loose spot in the bore. Basically unrifled. logically, if it was off centered you would see all the lands and grooves, but half of them starting ahead of the others. Most reamer throats are no more than one caliber in length and the first three picture sort of indicate that to be the case. The rifling appears to be gone well beyond the cutting length of the reamers throat cutting flutes. But it's hard to say. It's an oddity for sure.