Issues closing the bolt.

[Herd Thinner]

I have never had this issue until 300 win mag and I think I know the problem but need some advice. I am using lee dies first of all. I have a different set on order but for now its lee. For some reason on my 300 win mag loads 97 percent of them I couldn't close the bolt. Of the 3 percent that did close only 1 percent ejected smoothly. Its a virgin gun for one but I am guessing when full length sizing it didn't size properly or am i missing the boat. I have a case gauge. They all are in spec. Case length is at 2.610. Col is 3.340. The fired cases have no signs of any kind. One thing I did notice on a few cases that got stuck were light indents on the neck towards the body if that makes sense. Any guidance would be helpful. Thanks in advance.

 

[supercorndogs]

there is a company that makes a die to form the area directly in front of the belt. is this brass fired from a different gun. if you full length sized it enough and it will not chamber this is where your problem lies. if you are expanding this section enough in your gun to not chamber after a loading i would suggest you back your load off some. i use my lee collet die for my 300wm and would not trade it for anything. i get very low sd using it over neck an FL sizing. using to much lube when you FL will leave indentations on the shoulder

 

[witchhunter]

Mark the entire case and bullet with a sharpie then chamber. Your problem area will be identified by a scuff mark. Your case may be too long, your bullet seated to long into the rifling or you may not have your sizer die adjusted properly.

 

[buffybuster]

Remove all possible variables.

-Get some new factory ammunition, test fire your rifle with those loads. If they function normally then setup dies based upon those cases.

Or

-Get Brand New UNFIRED brass, chamber check in the rifle, they should chamber easily, if so load those. Then setup dies based upon those cases.

Lee Dies can load good ammunition. Nothing inherently wrong with them.

If the new ammo or brass won't chamber easily, then check the extractor as it may not have the clearance to snap over the rim.

 

[ZombieMonkey]

Several things could be causing your issues.

-You may not be bumping the shoulders back enough. Have you used a comparator to measure the brass headspacing of freshly fired cases vs newly resized cases? If you're getting marks on your necks as you say you are, it sounds like the source for you're hard closing of the bolt and heavy extraction are due to some sort of headspace issue. Does this rifle chamber factory ammo easily? (Most likely based on your description)

-You could have a tight chamber and need a small base die (Less common and I would not fool with unless you are sure this is your case)

 

[Twoboxer]

. . .
-You may not be bumping the shoulders back enough. Have you used a comparator to measure the brass headspacing of freshly fired cases vs newly resized cases? If you're getting marks on your necks as you say you are, it sounds like the source for you're hard closing of the bolt and heavy extraction are due to some sort of headspace issue. Does this rifle chamber factory ammo easily? (Most likely based on your description)

-You could have a tight chamber and need a small base die (Less common and I would not fool with unless you are sure this is your case)

Agree. Most likely insufficent shoulder bump. If you don't have a comparator, you can try screwing the sizing die in 1/8 turn more and resize/reload one of the cases that the bolt wouldn't close on. If it works smoothly, you've identified the problem and can then get a comparator to properly set your sizing die.

 

[CharlieNC]

Until you use a headspace comparator you are in the dark! Simply setting the die according to the mfg recommendations means you are either sizing the brass too much, or too little (which sounds like your case). Both of these conditions are bad. Get one and learn to use it to avoid these problems.

 

[LBZ]

Until you use a headspace comparator you are in the dark! Simply setting the die according to the mfg recommendations means you are either sizing the brass too much, or too little (which sounds like your case). Both of these conditions are bad. Get one and learn to use it to avoid these problems.

^^^^- This
Then and only then check out Innovative Technologies - Reloading Equipment if needed, which if you are headspacing off the shoulder, you should not.