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Discussion Starter #1
I loaded a few test rounds of IMR4350 and 150 grain CoreLokts to 3.300" OAL but discovered they won't allow the bolt to close and it feels like the cartridge is too "long". I double checked the OAL and it is under the max OAL of 3.340". Further info is that:
1) I neck-sized the cases from Federal factory ammo I had fired from the same gun and the case length after firing was .008" under the max length
2) With shorter rounds (OAL of 2.990" using Win 748 powder) I have had no problems with feeding (accuracy was not what I hoped for though)
3) I also had the headspace checked by a smith using go/no-go gauge and was informed that all was well on that end.

Appreciate any suggestions as to what are the most likely culprits I should be checking for to figure out what is causing the problem?
 

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With my 7mag, after firing either factory or reloads, a regular sizing die will not allow my brass to rechamber. I have to use a small base sizer and everything works OK. Full length sizing with the regular RCBS die would not get the brass back to size I needed for my tight chamber.
 

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I'm with castaway on this one. You are confusing "headspace" with "overall length". They are not the same but either can keep you from chambering a round.
you said "it feels like the cartridge is too "long". " It probably is but not overall. It is too long from the case head end to the midway point on the shoulder of the case (this would be headspace). The 'go' - 'no go' guages just make sure this internal dimension in your gun is within SAAMI standard for chambering.
If you screw the die down just slightly ...a little at a time just until you can chamber the empty case you should be good.
 

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You could smoke a case,with a candle, after resizing it. Let it cool, feed it into the action and gently close the bolt. Reopen and pull out slowly. Look to see where its hitting.

I had a problem like this just recently and it turned out that I was using ashellholder for a Ultra mag and not for the WSSM that I was loading. The shells went in easily but the holder was slightly thicker than the one that was needed. The shoulders were not reforming and causing a tight bolt.

HWD
 

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IMO the reason the bolt won't close is the bullet is hitting the land/grooves and when you back the bullet more into the case then it will will work. All bullet ogives are differnent which will cause the OAL to differ.
 

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rifling marks on the bullet

The only thing I don't see mentioned here (and I could well have missed it; if so profuse apologies humbly offered) is a recommendation for a visual check on the anterior surface of the bullet for "rifling smudges" where, as the last poster likely accurately pointed out, the bullet may be engaging the lands prematurely because of the phenomina he describes. Different ogive contours in bulles of different styles and manufacturers. If you find these marks, you'll have proof of the cause of the difficulty.
Best Regards,
s.
 

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Discussion Starter #9
Thanks one and all for the input, the info provided gives me some pretty good tips to work on and try to figure out what the culprit is.
 

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Here is a way to trouble-shoot your problem.

0. check case length of fired case.
less than or at max length ok-use it.
over max length - trim it to the proper length and clean the mouth of burrs

1. see if a fired, unsized case will chamber.
Yes, continue.
(no? your load was too hot and you need to reduce it and full size)

2. neck size case and see if it will chamber ( if you are using a full length die then adjust it to size only the first two-thirds of the neck)
Yes, continue.
No? you need to repeat second step with a different case making sure to clean and lubricate the inside of the neck. Make sure the outside of the mouth is burr free.
Retry it and if it still won't chamber then your pushing on the neck of the case hard enough to set it back into the shoulder - the expander may be rough or too large. With the proper lube it should slide through without pushing the shoulder back. get a new TAPERED expander. go to step 0

3. Seat a bullet in the neck sized case and see if it will chamber
Yes, continue.
No? Check the case neck diameter with the bullet seated. Is it over max?
Yes, check bullet diameter and case mouth wall thickness.
If the bullet is oversize send them back. If the case wall is too thick either inside or outside ream it to the right size. go to step 0 with a different case.

4. load a round with primer, powder and bullet and see if it chambers
yes, load em up!
no? go to step 0.

I hope this helps - if you have any questions feel free to mail me at
[email protected]

PaulS
 
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