HELP Resized cartridges will not enter the chamber?????

Z

zeke mccune

Member
Hi:

I recently began shooting a 7mm Rem Mag. that had been re barreled. The full length resized cartridges will not begin to chamber in the new barrel. Yes, I am attempting to use the brass that was previsouly fired in the orginal barrel.

Factory ammo will fit in the chamber and the fired factory shells that were fired in the new barrel will chamber in the new barrel. The shells that were fired in the old barrel and full length resized will not chamber in the new barrel. I tried two different FLS dies and had the shell holder touching the die.

I checked all of the dimensions against what was shown in the reloading book and I am well under those dimensions for both fired and resized shells. I painted the cases with a marker to see if here were any rub marks that may indicate a tight spot but there were none.

I called a local bench rest gunsmith whom I have tremendous respect for, and he suggested that I purchase new brass as the old brass had been blown out in an oversize chamber thus causing my problem. If the resized brass is well under the dimensions shown in a reloading book then it must indicate that I have an undersized chamber in the new barrel. Am I correct in assuming this?

What are your thoughts about a cure for this problem? Would a new chamber be a cure? Or perhaps a "custom" die would solve my problem.

I must say that the chap who did the rebarreling was a very skilled bench rest gunsmith who has passed away.

Any suggestions?

Tia,

Zeke
 
Sounds like to me that you have got a very nice tight chamber. You need to measure the shoulder lenght of the new brass fired in the new chamber both before and after you have full lenght resized. Then do the same with the old brass. Also you need to measure both cases just above the belt after they have been full lenght resized. As little as .0002/.0003 spring back at the belt after the case has beed full lenght resized is enought to keep the old case from chambering. This is not uncommon at all for a nice custom chamber.
Chet
 
I painted the cases with a marker to see if here were any rub marks that may indicate a tight spot but there were none.
Click to expand...

This is strange. Let me see if I have it right.

You took cases fired in the old chamber, FL sized them, put marker all over the case, and tried to chamber the cases but failed.

Moreover, the marking on the case was undisturbed. That's what is strange.

Belted cases all have one problem area. That's the case just forward of the belt. It grows, and while some dies are better than others at pushing this back (a collet die specifically designed to work on this area), no die will work on this area forever. You can test for this by sacrificing one older case & file down the case just ahead of the belt. After you've filed it down, (i.e., cheap mans' turned it down), mark the case with magic marker & try to chamber.

Another thing to be aware of is that after you size a case, it will spring back some. How much depends on how hard it is, which in turn depends on how many times it has been cycled (loaded & fired). As a guess, if your old chamber was oversized (could still be within SAAMI), the base may have grown enough that when FL sized, with the inevitable springback, it will not chamber. That should show with a micrometer, though measuring the at case head.

A third possibility is the the shoulder hasn't been set back far enough. Since for SAAMI specifications, belted cases headspace off the belt, the shoulder is not specified. But that's how most of use who shoot belted cases set them up, to headspace off the shoulder.

I don't think this is likely, but you probably need to check.

Finally, the case may just be too long, and need trimming. Unlikely, though.

The best advice you've already been given: buy new brass.

And watch the area just ahead of the belt for growth.
 
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The easist and most cost effective cure is new brass, by the time you rechamber or pay for a custom sizing die you will have spent more money than new brass would cost.
 
So many things could be at fault so lets start with some basics, and don't take this wrong but,

1 How long have you been reloading? Have you succesfully reloaded for magnum rifle before? If you are a novice I suggest you get with someone that has experience.
2 Have you tried chambering a re-sized case, not a cartridge? (seperate a case problem from a loaded round problem)
3 Try lubing the inside of a neck before sizing one, some brass is soft enough at the shoulder to have the expander stretch it as you pull down.
4 Is the shell holder the same brand as the dies? Believe it or not they are not all the same, and a few .001 can make all the difference
5 I have found with my custom chambered mags that die touching the shell holder is not enough, I need to set the die for a noticable thump to bottom out the handle without a case.
 
Thanks for the replies!

Hi:

The plot sickens!

I measured the dimension from the base to the shoulder and the unfired, the resized and the fired all came out to be 2.055". Now the reloading books say that this should be 1.972"-1.970". This means that my cases are .083"-.085" too long! How can such a descripency be? Are the loading books wrong? Are these factory loads and resized shells too long? There is no way that I can put that long shell in that short chamber! The book, the sizing die manufacturer, the maker of the chambering reamer and the ammo manufacturer must not be on the same page !

The cases have been trimmed to be .005 under the length of 2.500" so they are not too long. The neck diameter is listed at .315". My loaded shells measure .310" and after being resized, they measure .303". The necks are not too big.

The dimensions at the belt are .528 for both resized and new shells. The book calls for .532". The dimensions right in front of the belt are.508" and the book calls for .513". so I am not too large in these areas.

I have no idea as to what to do next and I hope that you people can solve this mystery as to why I can not chamber a round in this rifle.

Stay well my friends,

Zeke
 
Hello to All:

To Cliff.

I have been reloading since 1956.

Have been reloading belted magnums since 1961.

I tried shells that had been resized and no go.

The die and shell holder are the same mfg.,RCBS.

I am bumping the ram against the die.

Thanks for the suggestions,

Zeke
 
Here is the Saami spec sheet of both the chamber and cartrigde looks like your measurment of the new fired case in the new chamber is very close to the Saami standard. Your fired case 2.055 Saami chamber 2.0483 .0073 differents looks ok to me. very close to Saami.
Chet
View attachment 13239
 
My guess is that your FL die is long or your shellholder is too tall. Or both. In 8 years of troubleshooting similar problems in retail reloading business, I would say this problem happened on average of twice per week. Off the shelf dies frequently come too long. Or if you want to look at it the other way, factory chambers are coming too short. Whatever way you choose to look at it, the resulting problem is the same; a guy buys the FL die, threads it down to touch the shellholder, and soon finds out that his brass won't go back in the gun.
Three simple fixes:
cut .015" off the top of the shellholder with a carbide end mill
cut off .015" off the bottom of the die and re-radius and re-polish
buy new brass

Good luck
 
Hi Goodgrouper:

Wouldn't this result in pushing the belt back .030"? Is this a good thing?

I have done this with dies and/or shell holders for rimless cartridges but not for the belted cartridges.

I have also had to alter the die setting for rimless cartridges that were cut too deeply. Much easier fix.

Thanks so much for the help,

Zeke
 
Hi:

After sleeping on this problem, I got an idea. Since all of the dimensions of the ammo are correct, then it must be that the chamber is the culprict.

I took a fired and resized shell and cut the neck off at the junction of the neck/ body. Then the cartridge entered the chamber as it it should! Conclusion, the chamber is cut with a tight neck! Now to confirm my theory with a Cerrosafe chamber cast,

If the chamber indeed has a tight neck, then I will turn the necks to get proper clearance. Factory ammo will enter and extract without any problems. The factory primers showed no signs of high pressure.

Thanks for all of the help,

Zeke
 
zeke mccune said:
I took a fired and resized shell and cut the neck off at the junction of the neck/ body. Then the cartridge entered the chamber as it it should! Conclusion, the chamber is cut with a tight neck! Now to confirm my theory with a Cerrosafe chamber cast,
Click to expand...

Conflicts with

Factory ammo will enter and extract without any problems.
Click to expand...

It's beginning to sound like it is the die, except -- I though you'd tried two different dies?

Yes, do the cast.
 
zeke mccune said:
Hi Goodgrouper:

Wouldn't this result in pushing the belt back .030"? Is this a good thing?

I have done this with dies and/or shell holders for rimless cartridges but not for the belted cartridges.

I have also had to alter the die setting for rimless cartridges that were cut too deeply. Much easier fix.

Thanks so much for the help,

Zeke
Click to expand...





No, it won't. Die manufacturers don't make dies that go all the way down to the belt because belt thicknesses (or widths) vary greatly between brands. And you're only taking just a bit off the die or shellholder anyway and that's far under the possible overlaps of tolerances. So basically, you can just forget the belt is even there and just set your die up just like you would for any other cartridge headspacing on the shoulder.
Hope this helps.

Btw, the tight neck diagnosis doesn't sound viable to me because, like Charles said, factory ammo wouldn't go in either. Guess it could be a "snug neck", but odds are that factory ammo still wouldn't go in very well.
 
Describe exactly what you mean when you say "will not begin to chamber".

Can you force the bolt closed on an empty resized case? If so, what are the neck measurements before and after. Lube the bolt lugs before you try this.
 
Hi Wilbur et.al.:

Good for you to take time to think of my problem!

When I say the the case will not begin to chamber, I mean that the bolt still has to move about 3/16" before it is in battery. The case will drop out when the rifle is stood verticaly.

The neck on the fired measures .317
The neck on factory loaded ammo measures .310
The neck measures .310 after sizing
The expander ball in the FL die measures .281
The neck turner pilot measures .282 but will NOT enter a sized case neck! This pilot is supposed to be used on re sized case necks! The i.d. of the neck is .280 after bieng resized with the expander ball.
The necks measure .015 thick

I turned the necks on a couple of cases but that did not help.

I ground the top of the shell holder down but that did not help

I will "turn' the base of the shell off at the belt and right in front of the belt to see if that is the problem. If this is the case, then I may need new brass and/or a custom resizing die.

I will make a chamber cast as soon as i get some tips as to how to do it. It has been 45 years or so since I did the last one! Lol
Again, thanks for the help,

Zeke
 
Hi All:

I am planning to send 5 fired cases to RCBS and see if their Small Base die will solve my problem. If so, the SB die is less than $39.00. If the SB die does not solve the problem, then a custom die for about $53.00 is in my future.

I am now convinced that the problem is with the base of the shell that is just in front of the belt is too large! New brass will not be the answer! It would be the same song but a different verse!

Again, thanks for all of the help,

Zeke
 
The collet die will let you get more reloadings out of a case. After a point, it won't. At that point, a small 3-cornered file will let you get a few more -- there is a tiny amount of brass just forward of the belt that the collet die won't get.

I know all this because my long-time shooting buddy and IBS 1,000 and record holder, Joel Pendergraft, went through all of this with his .300 Ackleys. Yes, he used the Larry Willis collet die.

His eventual solution? Turn the belts off the case & cut a chamber to match that. Problem solved.

These days, aren't there a number of 7mm magnums not on a belted case? I know there are plenty of wildcats, but aren't there factory offerings?

Finally, don't forget Mike Bryant's (and others) recommendation. New Brass.
 
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