I've been reloading for about 2 years for one caliber - 300 rum. My last trip to the range, I had one round that I couldn't close the bolt on. After taking the round apart, I still couldn't chamber the brass. The other night, I chambered 40 primed cases that I have ready to load and about half needed much more effort than normal to close the bolt on, other half are fine. All cases have been fired 3-4 times and are within spec for length and I cannot see any other differences in the brass. I am trying to figure out what is causing this.

Is this a sign the brass has reached end-of-life or could this be caused by the shoulder being pulled slightly on some when resizing?

Thank you

I have the same problem w/ my .260ai. I'm on my 11th firing & some of the brass is very difficult to chamber. I am assuming it's work hardening. 11 firings though, I can't really complain.

One thing that can happen when you are full length resize them is that the brass in the body of the case gets thinner and it thickens in the shoulder and neck area. Check and make sure the loaded necks are not getting too thick for your chamber. If you are squeezing the cases down a lot each time you resize them it happens quicker.

My first thought would be that the headspacing is too close--have you turned your sizing die down ever so slightly?? Turning it about 1/8" could make the difference.

Fjord may be on to something. I had some brass that began to be difficult to chamber when loaded, however, unloaded resized brass chambered fine. The necks had thickened so that when you seated a bullet the diameter of the neck was too alrge for the chamber. Take a round that won't chamber, pull the bullet, resize it as normal, and try to chamber the brass. If it chambers, seat a bullet, if it now does not you need to turn you case necks or buy new brass.

Thanks for the replies.

It could be that the shoulder and necks are getting thicker - I hadn't thought of that. I haven't adjusted my sizing die yet because half of the cases still chamber just fine. I'll see if I can take some measurements of the neck thickness tonight.

I've got sized and primed brass that is very difficult to chamber without a bullet seated to begin with. Maybe my sizing die does need some adjustment.

Headspace too close,back up the shoulders by.002"(1/36 turn of the die is.002")at first,if it chambers with difficulty,add .002".(1/18 turn of the die means .004").Fireformed brass will vary(length) and your sizer will vary length of your cases.(1/8 turn of the die is .009"...

Headspace.

The harder the brass gets, the more it springs back. When you size the case, it will spring back a little. If your headspace is tight to begin with and your brass begins to spring back more and more, then they'll get harder to chamber.

Thick necks, Hell no! Factory necks are so oversized that you would need 30+ firings to make them too thick.

I know you know this, but bear with me-

It will chamber hard for 2 reasons, improper sizing or improper bullet seating/crimping.

Size the brass, then check all of them for chambering.

If they chamber fine then seat the bullets, or maybe just do them in batches of 10 at first and check for chambering problems.

It will be either one or the other, but better to figure out which one first rather than chase your tail trying to fix the problem.

Hi Mark;using the Stoney shoulder cartridge headspace gauge I find out differences up to .004" with fireformed cases,(sizing)the problem was "dirty " socket pocket hole,using the primer uniforming tool,solve the problem( hard bolt chambering was caused by it.Backing up the shoulder.002",having high primer(.004'") cases were hard to chamber...

Last night I took all of your suggestions and did some experimenting.

I incrementaly turned down the sizing die, resized, and then tried chambering a really tight case. I kept doing this until I was able to chamber all tight cases smoothly. I found it took about 1/8 of a turn on the die to get there. Then, I seated a bullet and chambered it. Result - chambered very smooth. This problem appears to be fixed.

Thanks everyone for your help!

Last night I took all of your suggestions and did some experimenting.

I incrementaly turned down the sizing die, resized, and then tried chambering a really tight case. I kept doing this until I was able to chamber all tight cases smoothly. I found it took about 1/8 of a turn on the die to get there. Then, I seated a bullet and chambered it. Result - chambered very smooth. This problem appears to be fixed.

Thanks everyone for your help 1/8 of a turn of on the die to get there,means backing the shoulder by.009"",how do you adjust the sizer in the first try,for sure with .009""you have solved your problem,(.009" is quite a headspace way to solve it?

Brass springs back. Just because you move the die down .009" don't mean the shoulder will move the same.

I turned the die down 3 seperate times to get to the 1/8 total and resized between each. The 1st turn, the brass still wouldn't chamber or if it did, was very tight - just being able to close the bolt

2nd turn, it would chamber but still very tight

3rd turn was a charm - the brass chambered without difficulty.

quote:

Posted 13 September 2005 09:50
Brass springs back. Just because you move the die down .009" don't mean the shoulder will move the same.

Cases dont springback,when one hit the shoulder,1/8 turn of the die is .009"(backing the shoulder).The problem when one adjust to back up the shoulder by .002" is to take under consideration that fireformed cases will vary to the datum line on the case shoulder;the sizer will of course back up shoulder by .002",but if your fireformed"cases vary ,the sizer will back up your cases all the same way,but cases fireformed(some will get a couple of .001")more from the case head to the datum line on the case shoulder,the sizer will only bach up the shoulder by .002",it is set up this way?

Sometimes the neck expaner will pull the shoulder forward a scosh. Lube the neck shoulder junction inside with a bit of case lube on a Q-tip.
Good luck!

quote:

Originally posted by rejpelly:

quote:

Posted 13 September 2005 09:50
Brass springs back. Just because you move the die down .009" don't mean the shoulder will move the same.

Cases dont springback,when one hit the shoulder,1/8 turn of the die is .009"(backing the shoulder).The problem when one adjust to back up the shoulder by .002" is to take under consideration that fireformed cases will vary to the datum line on the case shoulder;the sizer will of course back up shoulder by .002",but if your fireformed"cases vary ,the sizer will back up your cases all the same way,but cases fireformed(some will get a couple of .001")more from the case head to the datum line on the case shoulder,the sizer will only bach up the shoulder by .002",it is set up this way?

In my experience brass does indeed for sure springs back during the sizing process. It is a well proven fact that brass springs back. You can't argue to the contrary.

Case in point: I had a RCBS FL die that sized R-P brass so that they would just barely chamber. I attempted to use the very same die to final-form 22-250 from 243 and the suckers would not chamber. The shoulder would spring back past that happy point that made closing the bolt a chore. I even annealed the cases. Did not help enough. So, brass does spring back.

Using a FL( RCBS)sizer how much does it spring back;a couple of .0001",I cannot see it on the Stoney Point gage,only talking about one caliber...

quote:

Originally posted by hawkins:
Sometimes the neck expaner will pull the shoulder forward a scosh. Lube the neck shoulder junction inside with a bit of case lube on a Q-tip.
Good luck!

Very good advice, I second that scosh!
bigbull

Originally posted by hawkins:
Sometimes the neck expaner will pull the shoulder forward a scosh. Lube the neck shoulder junction inside with a bit of case lube on a Q-tip.
Good luck!


Very good advice, I second that scosh!
bigbull I lube the neck,no problem with that,(same amount apply),the problem is" springback" using the sizer,when one touch the shoulder if you adjust the sizer for 1/8 of a turn,it means backing up the shoulder by .009" or very near it,springback or not,springback using a fl sizer is it a myth ...

It is not a myth. Read my post.

quote:

Originally posted by Ralph Hyrlik:
It is not a myth. Read my post.

You,gentleman member,you didnt answer why one is touching the shoulder of the case,1/8 of the turn of the sizer is not .009",springback or not ,that was the question,not read your post...

Lookit,

Why is it that one case chambers and the other does not, if it is not brass springback?

quote:

Originally posted by Ralph Hyrlik:
Lookit,

Why is it that one case chambers and the other does not, if it is not brass springback?

Ralph just bear a little more and I will find what I am looking for,a sizer will size with no springback,meaning if one adjust for .002",the sizer will do that,only speaking about the sizer,if there is some variations about the sized cases,if the sizer is not "ïnvolved"something else is,just talking about the sizer,using the Stoney Point gauge some cases have .001" more from the-case to the datum line on the shoulder(Fireformed or sized) than the others,I didnt touch the sizer they come up with .001".( the sizer should make them all to come out with the same case-head to the datum line on the cae shoulder,but cases that have .001"stay that way...

What would you say the problem is if you have once fired brass, sized so the shell holder and die touch and not primed and no bullet, but will not chamber fully? I have tried two sets of dies and and shell holder with the same result. 270 WSM if it makes a difference.

We're not communicating.

My sizer is adjusted to cam over at the shellholder. No more adjustment can be made.

Fired, then sized, factory brass chambers easily. Brass made from 243 Win. will not chamber. The neck is not the issue with this brass, but rather the shoulder isn't being pushed back far enough. It springs back.

Ralph;fireformed brass may measure differently due to alloy and temper "variations" in the brass,also work-hardening,wich results re-sizing and firing,will have an effect.The type and amount of "lubrication" applied to the cases can have an "effect" on the sized dimensions."Variation" in the lube technique should be deal with.If one sized the cases to cam over,the more pression you put on the case,"hard siing compare to smooth sizing(if one have to use very hard pressure on sizing cases ,I have no doubt that the cases will springback,I can feel the springback by myself;is it possible that springback is an operator error,what is handle "smoothly "will have a tendancy to come out this way...

Ralph;the problem is concerning fireformed brass,they will vary before one sizes them?,I think brass have a tendancy to return to their fireformed"dimensions",meaning is one adjust the sizer to back up the shoulder by .004",what happens in reality ,cause of "springback"(whatever that realy means? you will get either .004",.003",002",.001" and probably not backing up the shoulder,it is a way to explain hard bolt closing;but there are others things to consider...

Yes, the fireformed brass vary. I can feel some being sized more than others.

I use the least amount of Imperial sizing wax that I can get away with, fo the amount of lube on the shoulder does not influence the amount of brass moved.

I think that the harder the brass, the more it springs back. Since not every case is the same, there will be different amounts of springback in a given lot of brass. The only way to avoid this is to anneal after every firing.

I agree with you;thanks; take care.

I can think of several things that could cause your chambering inability, but the most common I've found is in your case shoulder getting blown out and the case no longer going easily into the chamber, sometimes not at all. Check your sizing die and make sure the bottom of your sizing die is making firm contact with the shell holder. That'll push the case shoulder back. I have two rifles that get the shoulders blown out, and my neck sizers simply won't bump them back so I use a shoulder bumping die (a full length sizer also works). Best wishes.

Cal - Montreal

Thanks for all the suggestions and help. I just got back from the range and the brass chambered and shot fine. Just in case, I'm going to buy some new brass and retire this batch that I had to push back the shoulder on. I can live with 4-5 reloads per case.

real simple experiment,..spin the die body in another 1/4turn and retry chambering. If it goes in,..then you know the shoulder has grown. I find the RUM to trash primer pockets moreso that wear brass out.

I only get about 6 firings in my match chamber in the 300RUM,...so you are right there at the end from what I have found.