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reloading for the s308 problems


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im having a bit of a hard time getting my 308 reloads to work with in my saiga. for some reason my bolt does not want to fully close. i am using a full length RCBS sizing die, and am trimming the case to 2.06" and seating the 147gr mil spec pull down bullet to the cannelure and a mild crimp.

 

here the round passed the "plunk" test

plunk

 

this is the result of a full charge (pulling the charging handle back all the way and letting it go)

nogochamber

 

any suggestions and help is greatly appreciated.

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Do you have a factory round.. if so and it seats, check your case overall length,measured tip to base. Maybe size a case and chamber it empty, could be your shoulder is off if the size die is improperly adjusted. Just because your crimping on the canular doesnt mean the length is correct. Bullet shapes can affect seating as a sharper o-give can seat further into the rifling before it hits the edge of the bullet. But usually seating too long will give you trouble in the magazine.

What is the plunk test?

Edited by utahhandyman
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ill get a picture of the reloaded rounds after dinner.

 

but factory round did was it should have done, so i then went and resized a casing with out changing anything, and it also chambered correctly.

 

the 147gr is loaded to 2.72" and the 168gr is loaded to 2.76"

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All of the .308 loading data that I have seen show a max case length of 2.015" and a nominal length of 2.005" which is what I trim to. If your case length above is correct and not a typo, that may be your issue.

 

edited for clarity

Edited by Spacehog
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oh yeah sorry, forgot a 0. case trim length is 2.006"

 

well i was checking my different loads i spotted something, didnt think much of it till now. all the rounds that i am having issues with are of the same casing, "Gavin 91" not to sure how a different mfg of brass would effect it from closing fully, but it think there lies my problem.

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Use calipers to measure the key case dimensions of the problem reloads versus factory ammo or a reliable reloading manual. Below .308 case dimensions are from the Hornady manual:

 

post-37530-0-98359300-1446089284_thumb.jpg

 

 

When you find the variance, it will point you to the problem. If you suspect it is the brass. Resize some reputable brass and compare again to the standards above. You should be able to find the issue with some careful measurement.

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Do you have a comparator ? Along with measurements Spacehog suggested. Measuring the ogive is a good idea though probably not an issue if they go into the magazine.. Compare your home rolled to factory OAL at Ogive.

 

This from Sinclair or Hornady comparator.

post-39558-0-92042500-1446090494.jpg

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I recommend getting a case gauge, which should tell you whether or not your brass is the problem.  I resize .308 using a Dillon die, which will actually resize to BELOW minimum dimensions if you just crank it all the way down until it touches the shell holder (don't do this).  So you have to use a case gauge to ensure it is only adjusted far enough to bring the brass into spec.  The Dillon dies basically achieve the same result as small base dies when adjusted to minimum using a case gauge.

 

If you really want to get anal about your bullet seating depth, RCBS makes their Precision Mic in this caliber.  I wouldn't screw around with the comparator like was posted above....  It won't tell you where the rifling lands actually start like the Precision Mic will.  I don't use one for the .308, but I do have one in 7mm-08 that I use with my Model 7 bolt action and it works very well.

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I would bet $50 that they are fat at some portion of the neck. A Lee factory crimp die is great for curing that and controlling it precisely. I use RCBS small base dies and a Lee FCD and it cured this problem in a match chambered 308.

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i made a dummy round last night using a LC 69 casing. i use a RCBS .308 WIN SB T/C die set P/N:15507 and am using the crimp on it, ive had issues with it before on over crimping and deforming the brass but have fixed it. my dummy round had no issues with chambering from out of a mag. 

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Did you pull out the stuck case and examine? I'd like to see if there are marks from the lands on the projectile. That would say you are seating too long. Obviously the stuff the other guys said above about trim length is relevant too.

 

I was dealing with variable neck size since some necks bulged when the bullet was seated and others didn't. No easy logic to which would do it. However the Lee FCD didn't care. It makes them all uniform. Worth it.

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