Sticking 308 cases
- Thread starter S&L7x57
- Start date
My thought is really clean the chamber, ensure all case lube is removed. Perhaps anneal and size after that trying again. Lots of good advise already posted. I would have
a 788 Remington a 700 not dam likely.
a 788 Remington a 700 not dam likely.
You must be aware of Remington bankrupt yet again, wonder why?. Ruger, Savage, CZ, also work out of the box. I rather doubt the marketing with" fix it up and this thing will perform" is the idea but please enjoy a laugh. I have them often when you fellow's mention Land Rover. This from a guy who"Just empty every pocket" with my CJ7.
S&L7x57
Well-Known Member
Yes, I probably did but surely if they were beyond resize they wouldn't have chambered happily once reloaded. They were always checked for length before reloading. Also I am not convinced that any of my loads were 'over pressure'. A few certainly got quite flat primers but there were no loose primers or striker hole witness. I was always well inside what I considered safe pressure/loads. Compared to some factory loads that I had tried, the primers were relatively rounded!
Perhaps I am misunderstanding your term stretched.
A few thoughts:
When you smoked the sticky cases and chambered again you observed contact occurring in a ring perhaps 1/3 up from the head. Suggesting that this is the area where the case is tightest in the chamber, post firing.
It may be that the chamber is quite tight. When you neck size, or FL size with die backed off for minimal shoulder bump, this portion of the case will not be reset. Even with a complete FL resize, pushing the shoulder all the way back, your die may not touch this portion much, if at all.
If so, a "tight base" die might be needed to squeeze it back closer to the necessary dimension.
Which dies are you using ? When neck sizing are you using a dedicated neck die, or simply backing off the FL die to touch the neck only ? Either should work.
After a couple of firings the brass may have expanded in this region sufficiently to make subsequent firings too tight for easy extraction. Depending on the properties of your particular make of brass there may be insufficient "spring back" to overcome this. Possibly you may even have a dud batch of PPU that is too soft, as your 'smith suggested.
A slightly rough chamber would certainly not help. If so it could be gently polished by yourself without having to take the barrel off. Might be worth doing anyway. A piece of e.g wooden dowel, the end wrapped in soft fabric for a snug fit in the chamber, a dab of metal polish (I like Peek), take out bolt, insert, then rotate by rolling between the palms of your hands. Clean thoroughly afterwards.
I'd first try new brass, preferably Lapua.
Also beware, if you are regularly having to lean on the bolt to extract that will be applying excessive forces to the the bolt lug contact surfaces, potentially leading to galling and wear. A lot of pressure on them, due to the camming action. Be sure to keep these greased (I just use automotive lithium/moly grease for CV joints rather than any fancy stuff). This is especially important with SS actions, which can very quickly gall if not kept greased.
If they are already slightly galled, or there is uneven pressure between them then that should be corrected immediately, it will only get worse. This is where designs using slightly floating bolt heads, or three lug "fat bolt" designs (I.e. bolt body diameter is larger than the locking lugs) that don't need guide slots in the receiver may have some merit.
Since you have noticed significant accuracy differences between neck and FL sized cases, that suggests to me that you may not have an optimal powder charge weight that is tolerant of the slightly lower internal volume of the FL cases v. the necked ones. Some adjustment of your charge weight may result in a load that works well in both situations.
When you smoked the sticky cases and chambered again you observed contact occurring in a ring perhaps 1/3 up from the head. Suggesting that this is the area where the case is tightest in the chamber, post firing.
It may be that the chamber is quite tight. When you neck size, or FL size with die backed off for minimal shoulder bump, this portion of the case will not be reset. Even with a complete FL resize, pushing the shoulder all the way back, your die may not touch this portion much, if at all.
If so, a "tight base" die might be needed to squeeze it back closer to the necessary dimension.
Which dies are you using ? When neck sizing are you using a dedicated neck die, or simply backing off the FL die to touch the neck only ? Either should work.
After a couple of firings the brass may have expanded in this region sufficiently to make subsequent firings too tight for easy extraction. Depending on the properties of your particular make of brass there may be insufficient "spring back" to overcome this. Possibly you may even have a dud batch of PPU that is too soft, as your 'smith suggested.
A slightly rough chamber would certainly not help. If so it could be gently polished by yourself without having to take the barrel off. Might be worth doing anyway. A piece of e.g wooden dowel, the end wrapped in soft fabric for a snug fit in the chamber, a dab of metal polish (I like Peek), take out bolt, insert, then rotate by rolling between the palms of your hands. Clean thoroughly afterwards.
I'd first try new brass, preferably Lapua.
Also beware, if you are regularly having to lean on the bolt to extract that will be applying excessive forces to the the bolt lug contact surfaces, potentially leading to galling and wear. A lot of pressure on them, due to the camming action. Be sure to keep these greased (I just use automotive lithium/moly grease for CV joints rather than any fancy stuff). This is especially important with SS actions, which can very quickly gall if not kept greased.
If they are already slightly galled, or there is uneven pressure between them then that should be corrected immediately, it will only get worse. This is where designs using slightly floating bolt heads, or three lug "fat bolt" designs (I.e. bolt body diameter is larger than the locking lugs) that don't need guide slots in the receiver may have some merit.
Since you have noticed significant accuracy differences between neck and FL sized cases, that suggests to me that you may not have an optimal powder charge weight that is tolerant of the slightly lower internal volume of the FL cases v. the necked ones. Some adjustment of your charge weight may result in a load that works well in both situations.
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That sounds like it could be a hollow in the chamber wall rather than a bulge. The case has expanded into the hollow forming a bulge which then is sticking and is the highpoint that has the soot wiped off. Can you try a simple straight edge along a fired sticky case body to see if it has a bulge/crown? Spin one on a sheet of glass? See if it rocks?
Alan
S&L7x57
Well-Known Member
Certainly worth looking at. Still doesn’t explain the random occurrence of the problem though!
Only some of the cases were overpressure/sticky? The overpressure loaded ones may have gone further beyond the yield point of the brass / conformed more to any aberrations in the chamber and then not sprung back sufficiently to clear?
Your gunsmiths suggestion of cleaning / polishing the chamber sounds like a way forward if only to eliminate that possibility.
Alan
S&L7x57
Well-Known Member
I will go that way if nothing else can be found wrong.
Sinistral
Well-Known Member
If you ignore the PPU cases for now, and fully resize the other donated brands your problem might disappear.
PPU cases vary at the web. More often than not my PPU cases are squeezed hard down to the shellholder.
In your situation I'd be trying that first before anything complicated. It'll cost you nothing.
S&L7x57
Well-Known Member
You are on the same track as me. I have some once fired Hornady cases to try. Obviously will have to FL size for the first test but I will NS the resulting fired cases and try them. If I get no sticky cases, I think we can assume that it is the PPU cases that were the problem. I do hope so!
If this doesn't work then polishing the chamber is the next move.
I did a lot of comparative measurements and could find no significant (more the .0005") difference in the sticky, non-sticky and once fired rounds from A N Other rifle and in fact the sticky cases were sometimes of smaller dimension!
S&L7x57
Well-Known Member
Yes, tiny amount of bulge 1/2 way down the case but exactly the same as the non-sticky cases.
It would only need a tiny bit for interference.
If it is a build up of crud at either end of the chamber or actually a hollow...your gunsmith could maybe check with a reamer? Smoking / engineers blue and turning the reamer in reverse would show if there was a hollow where it left a bit untouched without cutting and altering headspace perhaps?
Alan
S&L7x57
Well-Known Member
First 6 rounds loaded as before into FL sized Hornady cases donated by friend. Lovely group, average velocity within 10 ft/sec of previous batches and NOT A STICKY CASE AMONG THEM! Yeh!If you ignore the PPU cases for now, and fully resize the other donated brands your problem might disappear.
PPU cases vary at the web. More often than not my PPU cases are squeezed hard down to the shellholder.
In your situation I'd be trying that first before anything complicated. It'll cost you nothing.
Next for the test of these cases NS'ed only..... oh please let them be freely extracting!
If its only happening with reloads, probably want to measure the sticky ones against good ones, trim length could be an issue, also check where bolt sits against the receiver, could there be a small lip built up over time , or carbon deposits that are locking the bolt down somehow. But if factory ammo is also fine, get a mate to check out your dies, or make up rounds with a friends dies, I suspect you have a tight chamber, with over length brass, ( or loose with carbon build up)or badly set up/ possibly crap dies. ( also clean your dies in a de-greaser, petrol will do, and clean ) good luck with a very unusual problem.
S&L7x57
Well-Known Member
Yes, only reloads. Every case is checked for length and all are well under max. Bolt is not the problem, it is the cases getting physically stuck in the chamber. Gunsmith who inspected chamber saw no build up of carbon nor significant roughness. Dies are brand new and their product measure up well against new factory ammo. There is no problem chambering their reloaded rounds. The dies were cleaned before use and have only loaded a few dozen rounds. They have been carefully set up using the factory info and then the FL dies tweaked using advice from here. The fired brass from my 788 measures pretty much exactly as others' fired cases in their rifles.
We will see from the next test (of NS'ed Hornady cases) if the PPU cases are the problem.
If not, then I can sense a chamber polish coming on!
Your #10 post in my opinion could be the reason, your possibly very close to being under sized in a % of cases. Not every one as you mention, adding 1/8 or 1/4 turn on the full length resizing die may very possibly remove the problem.
I have been following this and i may have missed the fact that all your brass is new and of the same manufacture, if its not and your using a mix of batch and manufactures you are going to get various pressure in each case, under max load or not.
If i have missed any of the issues raised in my post then please accept my apologies, but it would be very interesting to know the outcome and resolve.
I have been following this and i may have missed the fact that all your brass is new and of the same manufacture, if its not and your using a mix of batch and manufactures you are going to get various pressure in each case, under max load or not.
If i have missed any of the issues raised in my post then please accept my apologies, but it would be very interesting to know the outcome and resolve.
S&L7x57
Well-Known Member
Yes, these were a bag of brand new PPU cases which I used as new cases (no problems) and only once reloaded did the sticking occur.Your #10 post in my opinion could be the reason, your possibly very close to being under sized in a % of cases. Not every one as you mention, adding 1/8 or 1/4 turn on the full length resizing die may very possibly remove the problem.
I have been following this and i may have missed the fact that all your brass is new and of the same manufacture, if its not and your using a mix of batch and manufactures you are going to get various pressure in each case, under max load or not.
If i have missed any of the issues raised in my post then please accept my apologies, but it would be very interesting to know the outcome and resolve.
I have now reloaded a batch of once fired Hornady brass (from another rifle) twice: 1st time FL sized, 2nd time NS'ed with no sticky cases at all in either batch.
So it looks like the PPU cases just didn't get on with my rough ol' chamber.
I am going to load another batch of both FL and NS'ed of the Hornady and shoot them at full range rather than the pip-squeak one I have at home to see how the groups compare and to check to see if there are any sticky ones in the cases that have been NS'ed twice.
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