Bolt won't close on one re load?

[thefitter]

.308 Rem 700 in AICS

I wanted to check the cycling of my first batch of re loads in the AICS magazine to make sure everything would feed.

I tried to load everything as long as I could because my headspace is 2.959, subtracting .040 gives me 2.919. But my OAL is 2.87 because that's the longest I can fit in the mags.

In the first 10 round mag I had one that I could not close the bolt on. Second mag had 2 that were tight but I could close the bolt.

I measured all 3 rounds and I can not find any real discrepancy in their dimensions from the rounds that cycled in and out perfectly.

OAL = 2.875
Ogive = 2.165
Shoulder = 1.630

These numbers pretty much match all the others.

What am I doing wrong? Thanks

[rsrocket1]

If you full length resized the case, did you ensure the case length is 2.015 or shorter? I found that the cases can grow as much as 5 mil during the resizing process. Also, be sure you gun chamber is cleaned of any carbon fouling.

[Ahhnother8]

Take the two that were "tight" and color them solid with a sharpie, then chamber them. Where are the scuff marks? Likely near the web.

[thefitter]

If you full length resized the case, did you ensure the case length is 2.015 or shorter? I found that the cases can grow as much as 5 mil during the resizing process. Also, be sure you gun chamber is cleaned of any carbon fouling.

Yes all FL re sized and trimmed to the same length in a Giraud. This batch was all processed EXACTLY the same.

If it was the chamber wouldn't it be the same with all the rounds? Thanks

[Gunsrruss]

First....

You didn't exactly get those shoulders pushed back enough. I also think your bullets are to long. I have a Rem 700 PSS in .308. I run 173gr Match bullets 2.84 OAL the book only calls for 2.80. When I size I Run the die down to the shell plate and then give it another quarter turn forcing the shell plate and ram down slightly. This way I know I am not leaving any space. This has worked for me for years, but there are those who will say I'm absolutely insane. I also use RCBS small base dies sense I also shoot automatics. I took all my Lee dies and sold them to some other person who thought they were the greatest. Good luck

[J-cat]

Or you overcrimped and buckled the case.

[thefitter]

Or you overcrimped and buckled the case.

Crimped?

[J-cat]

Yes. What did you use to seat the bullets? How did you adjust it?

[bjl333]

Yea, you probably crimped the bullets too much. Measure the neck of the rounds that wont chamber against the ones that will. I am willing to bet the bad ones are fatter.

[Whiterabbit]

I assume he said "crimped?" as a joke, meaning "I don't crimp", not "I've never heard of the concept of crimping"

I like the sharpie idea.

I had a similar problem, calipers just told me nothing, and I measured every darn where. Pulled a few and full length resized the same round a few times (a sharpie would have made this pretty darn easy), and eventually found the resize marks about 1/8 of an inch beyond the extraction groove.

When you sized the bullets, was there any space between the die and shellplate? literally less than a quarter turn (backing off the shellplate) was the difference between a tight fit in the chamber and perfect operation.

[Shoot-it]

It sounds like the shoulder is not pushed back into place enough that happened to me with my 243 when I first started reloading.

If it chambers factory ammo fine then I bet it's the shoulders.

Make sure the whole length of the shell fit's in the die in order to re size correctly.

[Shoot-it]

So what was the problem?

[StraightShooter]

I dont think you completely understand headspace. Headspace is the distance from the boltface to the datum line (midpoint on the case shoulder). You sound to be using the distance to the lands of the rifling in the barrel as headspace which it is not. As long as you are not jamming the bullets into the lands then there will be no resistance when you close the bolt but it sounds like you know that already. There are really only a few things that could be happening here as long as your brass in trimmed to proper length like you say it is. One could be that you arent full length sizing your brass enough therefore not bumping the shoulder back, therefore decreasing headspace. The best way to check if you are sizing enough is to take the firing pin and ejector/spring out of the bolt. Take your full length sizing die and screw it all the way down till you hit the shell holder with the ram at the bottom of its stroke. Back the die out 1 full turn. Run an unsized case through the die. See if it chambers in the rifle with the pin and ejector out. It may or it may be tight. Turn the die 1/8 of a turn and resize. Try chambering it again. Repeat this step until the following happens:

As you turn the die it will begin to make contact with the tapered walls of the case. Once it is turned enough the case will no longer chamber in the rifle because at the very beginning of the sizing process will push the tapered walls inward without restricting the upward movement of the shoulder creating a case that has too much headspace (too long to the datum line). As you continue to size the case in 1/8 turn increments it will continue to make the case grow in length until the die is adjusted down to there it is restricting the growth of the headspace. As you continue to adjust the die, checking the chambering in the rifle, it will go from either not fitting or being tight to there being absolutely no resistance at all and the bolt handle will fall by itself. This is because the die has now pushed back the shoulder of the case to below the chamber headspace dimension. If you get good at it you can get your rounds set up for zero headspace where you can feel the bolt drag on the case but it still closes with only gravity (with the pin and ejector out of course, once it is put back in this is not the case). In rare cases the die will bottom out before it fully sizes the case and you will have to either remove material from the bottom of the die or from the shell holder, both of which should only be done by some one who knows what they are doing.

Ok, thats step one. Once you know your cases are properly sized then load up a round and chamber it without the firing pin installed. If it chambers the same way then problem solved. If it now chambers tight again then the only other thing it could be is a donut inside the neck. This happens on some brass after is has been reloaded a few times especially if you are neck expanding. In this case, a sized case will chamber with no resistance but a loaded case will not. This is because seating a bullet pushes out on a donut ring on the INSIDE of the neck making the neck diameter slightly bulged. If this happens then you can either inside neck ream the cases or just throw them out as it is a sign you are pretty close to the end of the brass's life anyways.

[gau17]

+1 on brandon

Get yourself one of these from Sinclair.



I ussually bump my shoulders back .001-.002 back after firing.

[FLIGHT762]

+1 on brandon

Get yourself one of these from Sinclair.



I ussually bump my shoulders back .001-.002 back after firing.

Here's a recent thread also explaining some of the issues. I also use the Sinclair and Hornady headspace gauge.

http://www.calguns.net/calgunforum/showthread.php?t=366517