6.5 lrm Need help on neck turing.

[HuntFarther]

I have had the first 6.5 lrm reamer from dave kiff. My first 6.5 lrm was finished the week before the announcement of the 26 nosler. I played with it but could not hit what the nosler does so put it away. I have been playing with the best load without pressure and that is one hole 3180fps with the 140 hybrids. I did notice that I have a donut that has formed and I want to know how to turn necks and the cheapest but efficient route to go. I do want something that is capable to use in my lathe for quickness.

I must also state that I have used the initial bad brass from gunwerks and the turned brass also the brand new brass and all cause me a problem. I am at 260 rounds and my throat is still really good.

 

[el matador]

Make sure you're not bumping the shoulder too much when resizing, that will lead to donut problems for sure. Even with proper sizing I was getting donuts in my 270 wsm and I addressed the problem with a K&M neck turning setup. I got the sizing mandrel die, neck turner and cutting pilot. After sizing (neck or FL), use the mandrel to expand the neck down to just above the donut. Then neck turn with the cutting pilot and the donut will be reamed out. Of course you'll have to size the neck again before seating a bullet to get proper neck tension. This method works very well for me.

 

[HuntFarther]

I am only neck resizing. I have tried to do it in steps and everything just having heck. I am hoping will free up a little room and may pick up speed or is this just a pipe dream?

I was going to order the k&m in the morning. What do I need carbide or which one do I need? They have like five different ones. Thanks ahead of time.

 

[bigngreen]

I like to push the shoulder back a little and expand it up a cal, then trim the OD normally then neck it back and fire it pulling some of the trimmed portion up into the shoulder. If you start out when it's 7 LRM and trim into the shoulder with the same degree cutter then you neck down which shortens the neck putting a little of the trimmed neck into the shoulder.

 

[el matador]

K&M has 3 different kinds of pilots and you want the carbide cutting pilot. That's the only one that will ream the donut out. I use a little Hornady One Shot cleaner/dry lube on the pilot after every few cases to keep things running smoothly.

 

[longrangehtr]

What happens if I turn the 7lrm to .014-.015 a side then neck down? do I neck to like .308 or what. Sorry never said that very good.

 

[Rimfire]

Any way you look at it donuts are a pain in the ***. I will never deal with them again and always set the reamer up with the base / driving band of the bullet above the donut. I would mock up a dummy round, send it back to the smith and have them push the throat out a little and be done with it, never have to deal with it reoccurring.
Yes the donut can cause serious pressure problems. Take a fire case and drop a bullet into the neck, if you cant push it freely past the donut you have no release clearance and there is your pressure.

 

[HuntFarther]

Here is a quick question. How much expansion is ideal but not saami for throat design. You have say .014 a side neck wall thickness. Then how much room for the expanding case?

 

[el matador]

About .005" would be ideal neck clearance. Pretty hard to achieve that unless you specify your chamber specs and turn your brass to match it.

The reason I turn brass (other than for donut removal) is to get uniform neck tension. The Norma brass I've used has been pretty good and I don't feel the need to turn it unless I get donuts. Winchester and Rem brass that I've used has been more inconsistent so I'll turn the necks to make them uniform. Since all my chambers have plenty of neck clearance I only turn enough brass off to clean up 75-80% of the neck surface.

 

[HuntFarther]

So is that clearance a side or is it total?

 

[AZShooter]

Certain he meant total which is 2 1/2 thousands per side. I read on accurate shooter that some guys shooting the 284 win were having issues with too tight a bullet release dimension:

"Jerry Tierney, a past NBRSA 1000-yard champion and .284 Win "guru", has observed that overly tight chamber neck tolerances can cause accuracy problems. Jerry says "some guys who were running minimal neck clearance .284 chambers weren't getting the accuracy they expected. If you open up the neck to allow more clearance, say .0015-.002″ per side, that seems to solve the problems. I can't tell you exactly why–maybe it allows a 'cleaner' bullet release–but easing the neck clearance has helped many .284 shooters get better results."

To me that is still too tight for a hunting rifle. I agree with previous poster with a minimum of .0025" per side. Nothing wrong with .003-.004" per side either.


Just in case you didn't catch the trick to prevent donuts.... neck the 6.5 necks back to 7mm then turn the necks with the K and M turning tool so the angled cutter will remove a tiny bit from the shoulder.

I use my lathe in back gear for neck turning. I took apart an old lyman case trimmer and use the shell holder in my 3 jaw universal.

 

[HuntFarther]

Thanks You guys this really helped a lot. I will have the K&M ordered this morning and will let you know how things go.

 

[Canadian Bushman]

I might be assuming too much here but i think your problem may stem from running warm loads in a case that is prone to growth.

The excessive growth is causing donuts to form and now you have trouble seating bullet to the correct COAL.

If im incorrect im sorry if not your best bet will be to do as rimfire suggested and throat the rifle so the bullet base is beyond the neck shoulder junction or to ream out the donuts. I dont think neck turning is the proper solution here.

 

[HuntFarther]

I truthfull believe that the cases are just from way to much neck material. There is up .018 a side and neck shoulder is supposed to be no more than that and are .023+ and then as I neck to 6.5 I keep building up the problem. The new cases are .015 at the mouth and are .018 at neck shoulder junction.