Hey guys. I started measuring today and maybe stumbled on to something. First off I have a custom 300 RUM. I used some new brass today. This is the first outing since having the barreled action cerekoted. Nosler and remmy both. Noticed, out of the box, the ID was only .302. I just ran the necks up to the expander ball on the nk die to open them up. They sprang back and stayed around .3035. Took them out and shot a lot of about 20 each brass. Noticed that my SD was alot higher than normal. Also the necks seem to come out dirty. When I got home I checked the mouths. .307-.308. Can barely get a bullet back in spent cases. The reamer was a custom, .343 nk. The OD of the necks are .342. What do you guys think? Wall thickness on both brass lots are .016
should I be turning necks???
- Thread starter Dshooter
- Start date
I'm not so sure I'd say it the same way Mr. Mulhern said it but I agree.
My take on the problem:
How did you get that .302 measurement? Am I to assume that was the O.D. of a new shell out of the box? Is that measured with a caliper or a mike? That doesn't even matter and it was a stupid question on my part. You'd have to expand and then run the cases through a neck sizing die anyway.
Did you get a chamber print from the smith? Is he a reputable gunsmith? That O.D. of .342 is of a loaded round? Did a loaded round chamber easily enough or could you feel more resistance than expected? If I suspected anything was not right I'm not so sure I'd have pulled the trigger on them 40 times and expected a different result each time. Start with a call to your gunsmith and find the diameter of your neck chamber and that may mean getting a casting of the entire chamber. Again, I wouldn't pull the trigger again. If the outside of your necks are dirtier than they should be or more than you expected, it sounds like the neck chamber is too large, the loaded rounds are too small, or both. But definitely neck turning isn't in order yet.
My take on the problem:
How did you get that .302 measurement? Am I to assume that was the O.D. of a new shell out of the box? Is that measured with a caliper or a mike? That doesn't even matter and it was a stupid question on my part. You'd have to expand and then run the cases through a neck sizing die anyway.
Did you get a chamber print from the smith? Is he a reputable gunsmith? That O.D. of .342 is of a loaded round? Did a loaded round chamber easily enough or could you feel more resistance than expected? If I suspected anything was not right I'm not so sure I'd have pulled the trigger on them 40 times and expected a different result each time. Start with a call to your gunsmith and find the diameter of your neck chamber and that may mean getting a casting of the entire chamber. Again, I wouldn't pull the trigger again. If the outside of your necks are dirtier than they should be or more than you expected, it sounds like the neck chamber is too large, the loaded rounds are too small, or both. But definitely neck turning isn't in order yet.
My take on this, from your description:
1) It appears that you were describing neck ID, which was pretty tight, so I would suspect that your brass needs to be annealed. The dirty necks support this idea (too much springback), also, especially if these were full power loads.
2) You need to get precise/reliable chamber neck diameter measurement. If indeed, your loaded rounds are .342 dia. & your chamber neck dia. is .343, you don't have enough clearance. On a big magnum like yours, I would think a minimum of .003" difference between loaded round OD & neck dia. If this is a hunting rig, maybe .005" difference would be more appropriate. I would have thought your gunsmith would have advised you that the clearance might be marginal with this reamer, and that necks needed to be turned to make the rifle safe.
3) Like was said above, don't shoot it again until you have all this sorted.
1) It appears that you were describing neck ID, which was pretty tight, so I would suspect that your brass needs to be annealed. The dirty necks support this idea (too much springback), also, especially if these were full power loads.
2) You need to get precise/reliable chamber neck diameter measurement. If indeed, your loaded rounds are .342 dia. & your chamber neck dia. is .343, you don't have enough clearance. On a big magnum like yours, I would think a minimum of .003" difference between loaded round OD & neck dia. If this is a hunting rig, maybe .005" difference would be more appropriate. I would have thought your gunsmith would have advised you that the clearance might be marginal with this reamer, and that necks needed to be turned to make the rifle safe.
3) Like was said above, don't shoot it again until you have all this sorted.
Thanks for the replies guys! I will clarify a little better. I am using all new brass. Remmy and nosler out of the box. Using Starrett dial cal, measured neck ids to be the .302. Don't have an expander die so using neck die, ran the neck just through the expander ball. No sense in running them all the way into the die since they were to small to start. The neck tension was still around .005 when I loaded them. I have the reamer from PTG used to chamber the barrel. It is a .343nk. After firing the loads, the OD of neck measures .342 and ID is still tight to bullets. My assumption was neck turning because the necks are .001 smaller than chamber, as they should, but ID is still tight. I never did, but I will, measure od of loaded round.....as for the dirty necks, still out to lunch?
Thank you too sir. The gunsmith is a very popular, f/tr competitor, and known very well in this community. I won't mention names, as I'd discussed in the past, my unsatisfactory experience with him. I didn't want a tight chamber and it was never mentioned to me so I'm find all this out now. And especially with this caliber, there are only 2 types of brass readily available for it, of which both now will have to be neck turned.
SmokinJoe said:
If you are anti-neck turn, you can still ream the neck area to a dimension where you won't have to neck turn. Just another option.
Hold er...
OP says neck thickness of both lots of brass is .016. That equates to a loaded neck diameter of .340. It is a .343 chamber. His neck clearance is fine.\
If his fired round neck dieameter is .342 .... .001 spring back. His brass is fine.
Get a good bushing die and fidget with neck tention to get those ES numbers down.
OP says neck thickness of both lots of brass is .016. That equates to a loaded neck diameter of .340. It is a .343 chamber. His neck clearance is fine.\
If his fired round neck dieameter is .342 .... .001 spring back. His brass is fine.
Get a good bushing die and fidget with neck tention to get those ES numbers down.
BoydAllen
Gold $$ Contributor
In my experience, reaming necks does not improve the evenness of their thickness, and turning is not such a big deal that it needs to be avoided. I would do a light clean up turning of a few cases' necks, just taking off the high spots, as a test.
One issue is the difference between custom reamers and factory. Typically factory chambers have a slight taper built into their necks, this in recognition of the fact that unturned necks get thicker toward the shoulder of the case. If you have a chamber that was cut to a fairly close fit, with a reamer that it typical of the custom variety, with no taper in its neck, the clearance between the necks of your loaded rounds and the chamber will decrease as you approach the shoulder. If the clearance gets close enough it may interfere with a clean consistent release of bullets, which may be why you are seeing the increase in ES.
There can also be an issue with annealing. If a case is on the springy side, and thick necked (as yours are) they my spring back more after firing, than if they were annealed so that they were a little softer. Go slowly here, and do a lot of research before annealing, there is some of what I believe to be bad advice out there. Your observation of dirty necks may be related to this, because of a delay in sealing due to thicker, harder necks. It may also be related to the powder that you are using, and the pressure to which you are loading.
One issue is the difference between custom reamers and factory. Typically factory chambers have a slight taper built into their necks, this in recognition of the fact that unturned necks get thicker toward the shoulder of the case. If you have a chamber that was cut to a fairly close fit, with a reamer that it typical of the custom variety, with no taper in its neck, the clearance between the necks of your loaded rounds and the chamber will decrease as you approach the shoulder. If the clearance gets close enough it may interfere with a clean consistent release of bullets, which may be why you are seeing the increase in ES.
There can also be an issue with annealing. If a case is on the springy side, and thick necked (as yours are) they my spring back more after firing, than if they were annealed so that they were a little softer. Go slowly here, and do a lot of research before annealing, there is some of what I believe to be bad advice out there. Your observation of dirty necks may be related to this, because of a delay in sealing due to thicker, harder necks. It may also be related to the powder that you are using, and the pressure to which you are loading.
I appreciate all the helpful advice. I feel this is the best place to come on the net for problems like this. I wasn't looking forward to turning necks as this is a hunting/ELR steel shooting rifle, not a benchrest or f/tr. If that is what it takes to make it right then so be it, that's what I'll do. I will start with a light clean up of say .002-.003?? Or at least until it's concentric. I do have a redding FL bushing die on its way and I will use the TiNi bushings I already have for the .308. Have plenty of sizes here. Any advice on a quality, yet easy to use neck turner? Thanks again
GPat
Site $$ Sponsor
Alright, let's talk about measuring equipment. You mentioned .016 wall thickness on the neck. What are you measuring this dimension with? I've found that if you are not measuring the neck wall thickness with a ten-thousandth reading ball micrometer (one that you know how to use, and NOT one of those snap gauges that read to the 1/2 ten-thousandth), it's best to not even measure that thickness. Load a dummy round and measure that, it should be .004 less than your chamber nk for a hunting rifle.
With the variations from piece to piece, you may still have some necks that are thicker, but at least with this measurement you have a ballpark figure. One of your replies mentioned the figure of .340 (.003 total clearance or .0015 per side), but I would view that as the absolute minimum clearance for a hunting rifle. You'll be much better off with a loaded neck diameter of .338 which is a nice number because you can turn the brass to .015", which is easily done. .339 would be fine too (neck wall thickness .0155).
For your application, I would reccomend a PMA Model B, but I'm not here to push my product. If you want to discuss it, give me a call 260-246-5860 and we can discuss your options with PMA equipment or if you want to go in a different direction, I can help with that as well. Whether you go with a PMA or one of the other tools out there, I really think you need to neck turn for this rifle.
Pat
With the variations from piece to piece, you may still have some necks that are thicker, but at least with this measurement you have a ballpark figure. One of your replies mentioned the figure of .340 (.003 total clearance or .0015 per side), but I would view that as the absolute minimum clearance for a hunting rifle. You'll be much better off with a loaded neck diameter of .338 which is a nice number because you can turn the brass to .015", which is easily done. .339 would be fine too (neck wall thickness .0155).
For your application, I would reccomend a PMA Model B, but I'm not here to push my product. If you want to discuss it, give me a call 260-246-5860 and we can discuss your options with PMA equipment or if you want to go in a different direction, I can help with that as well. Whether you go with a PMA or one of the other tools out there, I really think you need to neck turn for this rifle.
Pat
Re: should I be turning necks??? Update.....
Ok guys update....I measured the loaded round, neck OD. They all read .338. My spent casings, only once fired the other day, OD reads .342. The ID of the spent brass is right at .308 or half thousandth below as a couple I had to force bullets to go in. The dirty necks, well, some the black stops right at the junction. A few the soot is just onto the shoulder. In the pics are a few of my ultra cases and a couple of my .308. The .308 necks, the soot stops around .060 before the shoulder junction, as it should be in my opinion....
Ok guys update....I measured the loaded round, neck OD. They all read .338. My spent casings, only once fired the other day, OD reads .342. The ID of the spent brass is right at .308 or half thousandth below as a couple I had to force bullets to go in. The dirty necks, well, some the black stops right at the junction. A few the soot is just onto the shoulder. In the pics are a few of my ultra cases and a couple of my .308. The .308 necks, the soot stops around .060 before the shoulder junction, as it should be in my opinion....
Attachments
Dshooter,
If your loaded round is .338 on both kinds of brass you have plenty of clearance. What you might want to do is check your neck wall thickness variance ( see Pat at PMA or Sinclair for the tool) and weigh sort your brass (do this for each manufacturer). Keep the ones out that are about equal in weight with the least amount of neck wall thickness variance ( same head stamp, whatever sample size group you want) load them up same as before and check your SD again but make sure you have pre-fouled the barrel. You can do the water volume test to if you want to go that far.
The soot issue may be because the load isn't hot enough to expand the neck out to seal the chamber fast enough.
Kind of a fast "down and dirty" answer. Let me know if I can clarify anything.
Take care,
Phil Hoham
Berger Bullet tech
If your loaded round is .338 on both kinds of brass you have plenty of clearance. What you might want to do is check your neck wall thickness variance ( see Pat at PMA or Sinclair for the tool) and weigh sort your brass (do this for each manufacturer). Keep the ones out that are about equal in weight with the least amount of neck wall thickness variance ( same head stamp, whatever sample size group you want) load them up same as before and check your SD again but make sure you have pre-fouled the barrel. You can do the water volume test to if you want to go that far.
The soot issue may be because the load isn't hot enough to expand the neck out to seal the chamber fast enough.
Kind of a fast "down and dirty" answer. Let me know if I can clarify anything.
Take care,
Phil Hoham
Berger Bullet tech
Shooting a king-kong magnum with 90gr plus of slow powder? Gonna see some residue on the necks.
Got the action cerakoted? Was the boltface trued or coated?
A caliper won't measure neck thickness, as the other guy alluded to. Ball micrometer and should read in ten-thousandths, or an ID reading tube mic of same calibration.
But...Inquiring minds and all that... How many rounds on your barrel? What did the brass measure oal to shoulder before and after firing?
Don't sweat the small stuff, guy. The KK magnums are barrel eaters. If you got 250 rds fired through yours already, probably time to order-up again. Maybe let Pac-Nor, Hart, or Shilen do a pre-fit job. Pull your barrel and give them bolt nose and boltface measurements to the receiver shoulder, they will dial you in and give you the chamber you want.
Really want a min oal chamber even with a KKM. Had a few KKMs 7-8yrs ago. Decided did not need the Barrel Scorching with every touch of the trigger. Call Sierra and ask their tech boys/girls how long your .300rummy ought to last? .30-378, .338rum, .300rum all gone and glad of it... Each to their own.
Might try shooting your same loads in the now chamber-formed brass and see if your concerns are alleviated. Better still some older brass you know had no issues.
If you shoot only handloads, check the oal of virgin and 1x fired brass on a Wilson Case Gauge, or RCBS Precision Mike; you might be very surprised at the variance.
If you are trying to shoot mild loads w/anything other than cast boolits in your KKM, there is some danger there. Too mild and you risk detonation. If you aren't filling-out your virgin brass to full chamber dimension, you probably don't want to go any lower. With fully formed brass, it wouldn't matter (within reason). Anything of full-length H&H Mag case dimension is too big for mild loading with typical magnum powders.
One other thought, Using Federal 215 magnum primers? The Primer specifically developed for KKM uses? Might want to, so to be sure of complete powder ignition. Maybe that is part of your smoked neck issues?
Got the action cerakoted? Was the boltface trued or coated?
A caliper won't measure neck thickness, as the other guy alluded to. Ball micrometer and should read in ten-thousandths, or an ID reading tube mic of same calibration.
But...Inquiring minds and all that... How many rounds on your barrel? What did the brass measure oal to shoulder before and after firing?
Don't sweat the small stuff, guy. The KK magnums are barrel eaters. If you got 250 rds fired through yours already, probably time to order-up again. Maybe let Pac-Nor, Hart, or Shilen do a pre-fit job. Pull your barrel and give them bolt nose and boltface measurements to the receiver shoulder, they will dial you in and give you the chamber you want.
Really want a min oal chamber even with a KKM. Had a few KKMs 7-8yrs ago. Decided did not need the Barrel Scorching with every touch of the trigger. Call Sierra and ask their tech boys/girls how long your .300rummy ought to last? .30-378, .338rum, .300rum all gone and glad of it... Each to their own.
Might try shooting your same loads in the now chamber-formed brass and see if your concerns are alleviated. Better still some older brass you know had no issues.
If you shoot only handloads, check the oal of virgin and 1x fired brass on a Wilson Case Gauge, or RCBS Precision Mike; you might be very surprised at the variance.
If you are trying to shoot mild loads w/anything other than cast boolits in your KKM, there is some danger there. Too mild and you risk detonation. If you aren't filling-out your virgin brass to full chamber dimension, you probably don't want to go any lower. With fully formed brass, it wouldn't matter (within reason). Anything of full-length H&H Mag case dimension is too big for mild loading with typical magnum powders.
One other thought, Using Federal 215 magnum primers? The Primer specifically developed for KKM uses? Might want to, so to be sure of complete powder ignition. Maybe that is part of your smoked neck issues?
Thanks for your input Hogan. All is appreciated. I know most on here are not fans of the shoulder fired cannons. I love them for ELR. There's nothing like shooting 1500yds with a cartridge good, supersonic, to 1780. To answers your questions, yes bolt and action where cerakoted. I will never cerekote a bolt again, especially on a custom action. It is the way I got it from stiller, and previous to cerekote, wear marks showed a very true bolt face and lugs. I have around 150 rds on barrel and at full power, as I'm shooting, barrel was estimated life of 1200 rounds and some even said 14-1500. The new brass shoulders are between .002-.003 shorter than fired brass so they shouldn't play much part in the equation. I have a ball micrometer on its way for correct measuring of necks. Yes, I am using 215Ms now. Before I was using CCI 250(could be part of it). These are full power Retumbo loads for my gun. 90.5 gr behind the 215 hyb. 90.7 gives me light ejector marks. The residue is going all the way to the shoulder and up part of the shoulder on several cases. I guess that's what bothered me most on the residue issue.
hogan said:
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