Tight Chamber? Need help/advice!

[GLTaylor]

Which resize die are you using? I don't see a "Type s FL neck die" in Redding's catalog.

Type S bushing style full sizing die in 6.5x284. I simply changed the neck bushing to a 25 cal once i reformed the brass from 26 to 25 cal.

 

[milo-2]

So, I recently got a new .25 cal barrel and a chamber reamer to shoot the new, long, 131 gr Blackjacks. I Bought the Krieger barrel and chamber reamer from Blackjack. Had the barrel chambered and put on my switch barrel receiver by my smith. Everything has gone well and the rifle shoots quite well for me. I'm on my 3rd reloading of my brass and I have begun to have some concerns.
I had a few case separations (4-6) and immediately thought I goofed up on my headspace. I have also noted some problems with chambering a FL sized case in the chamber. Some absolutely do not want to let the bolt close on the loaded round.
I have re-checked the shoulder bump twice and am right on target with an average .002 shoulder bump. Some are .001, some are just over .002, but historically I have seen this and attributed it to the differences in hardness in individual pieces of brass. I'm averaging .002 for the vast majority of cases.
I do anneal the necks of my brass.

I got to measuring my cases today and found that the web is rather small after firing. The cartridge is a 25-284. I'm using 6.5 Lapua brass necked down to 25 cal. and I am skim turning the necks for uniformity and to avoid a donut forming, Specs for both the Winchester and Norma 284 call for a case head diameter of .500. My Fired case heads measure .495-.496. Most run .495.
When I run my brass through the Type S FL neck die, the die only reduces the brass down to .495, and this only if I run the brass through three (3) strokes of the press in and out of the die. Obviously, the brass is still tight after I resize it.
I am certainly not a gunsmith, so I thought I would ask the braintrust here for your opinions.

I think I have decided that my chamber is quite tight. I bought a reamer to have this chamber done, so it has only been used one time on one barrel. Don't know if this makes any difference.
My thinking is that if I could somehow polish the chamber walls, I might get rid of some of the tightness and maybe loaded rounds would chamber easier - or at least with a lot less effort. Sometimes I have to beat the bolt down with my fist to get a round to chamber. Obviously, this isn't right.

I am also wondering if a very tight chamber base would explain the case separations I have experienced.

Is it possible that the chamber is gripping the brass too firmly and only allowing the forward portion of the brass to move when pressurized? I don't know. Just my conjecture, right or wrong. None of the cases have completely separated, but the imminent case head separation ring became visible outside the case and I verified its presence with a sharp probe inside the case body.
So what do you guys think? Am I on the right track, and if so, where/how do I proceed from here. Remember - I'm familiar with rifles, but I'm not a gunsmith!
Thanks in advance for all your good answers.
George

I am not going to read all the comments, yes your chamber may be tight, but also feel your die is not compatible with the chamber, not sizing the base area. You want your brass to grip the chamber lower on the case and work the area below the shoulder.
I would find a couple new pcs of brass and start measuring every aspect of it and compare to fired brass. Figure out where and why it is growing. Other than the case head area, brass cannot out grow chamber dimensions, so NO, tight chamber cannot cause it, so something is not right if you can feel case head separation.

 

[GLTaylor]

Ok. I just ordered some new 284 brass, since all of mine has been loaded and fired.
When i get the new brass I'll measure every aspect of it and re-measure at each firing to see what changes.

As suggested, i colored some brass with a sharpie then chambered it.
I expected to see more rubbing than i saw on the case heads. Still hard to close bolt, but little sharpie was removed. Just very lightly marked?

Photos enclosed. May take 2 trys

Do i just get more dies and hope they fit better? Suggestions?

 

[L.Sherm]

Call Blackjack and see if they or anybody else has ran into this problem and see if you can get a reamer print to see what there reamer is spec'ed at the .200 line.
You can send Whiddens some fired cases if all else fails and make you a FL die.
See what dies Blackjack uses.

 

[25WSM]

Two ways to fix this. One is send 3 fired cases to who ever is making your dies. Several companies will make a die that works with brass you send them. The cheaper fix is to polish the chamber slightly larger in the areas the die isn't sizing. This will let your brass expand slightly more letting your die be able to size it more. Making your chamber bigger makes your sizing die smaller. I do it all the time. I cut Chambers that are tighter than factory Chambers easily and some die sets are just to big to size custom cut Chambers. I'm talking about sanding less than . 001 out of the chamber. It will fix your problem either direction you go.
Shep

 

[Bob Wright]

Did this one chamber tight?
You could call Redding's tech line and get in the queue for some advice. They may want to see your photos and possibly your brass and die. Service may be slow at this time....

 

[GLTaylor]

Bob,
Yes, all of these chambered tight. You can close the bolt on them, but it takes some effort. Not smooth like it should be for a hunting rifle.
I checked specs/diameter at the case shoulder and the dia is correct per the Norma and Win 284 drawings? The head is the only "tight" spot.
Shep,
Thanks. I had already thought to ask my smith about sanding the rear of the chamber out some. Just wasn't sure about if that was a sound/safe idea...
L.Sherm,
Gonna call Blackjack tomorrow.
You guys are great. Thanks.