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Lar-8 making odd marking on the end of the casing.


ahb81

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First time out shooting my new lar-8, and its been awhile since I fired a semi-auto rifle, but I dont remember my M16A2 ever smashing the lettering off the back of the casing like this.  What would be causing this, or is it normal.  I assume its the extractor, but unsure.

Thanks,

Allen

post-973-136297267609_thumb.jpg

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Ejector hole inprint .

Might want to check to make sure it has no burrs on the bolt face or a raised section.

I wouldn't worry about it too much . If your a reloader ,some times you might have to take a fine flat file & dress up the case to make sure it will insert into the shell holder.

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Ejector hole inprint .

Yep, right there.  I've seen others mention this before on the RRAs, and they should break in a little.  In the future, it shouldn't mark the cases as badly, but you will almost always find the ejector mark.

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  • 4 weeks later...
  • 4 weeks later...
  • 1 month later...
  • 2 weeks later...

My new LAR-8 did a similar thing, though not as bad as he had.

dcsxgw.jpg

I approached mine as an over-gassing issue, but neither additional buffer weight, nor adjustable gas block helped. If the bolt rotated, the ejector swiped the head. Looking under a stereo microscope at the bolt face, it didn't have any obvious burr like his did in the pictures on page 1. What fixed my problem was rather low tech. I removed the extractr and ejector, chucked an old .308 case in the drill press. I put a dollop of 600 grit lapping compound onto the bolt face, lined the two up carefully and polished it using the brass case in the drill until the phosphating was just barely effaced. No more swipes.

While the fix bandaided the problem, it is still being caused by the bolt trying to unlock while the brass is still siezed to the chamber wall, so the problem is still one of timing dwell. The adjustable gas block was fussy to implement in that when set to where it would cycle one round, there was no consistent repeatable guarantee that the next round would cycle and that was using the same loads. I didn't want to have to tweak it each time I changed loads as well. I suspect the proper solution would be to move the gas port and block a little further down the barrel or using one of those folded back upon itself, longer gas tubes, if you can still find them. The ones with the extra stub hanging off of a manifold are not the solution. Actually, I never understood why they even exist.  <dontknow>

Hoot

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Just got home from the range not bad out windy and 57deg..The first 60 I ran through of Dag 7.62 German surplus showed nothing first cleaning took apart BC assy. and extractor when I found one side of pin hole a little elongated called RRA tech said was factory crimp on one side to keep pin, mention spring stiff to compress compared to 5.56 said was normal because larger round needed more force for engagement and extraction today's 120 were combination Dag[all gone] and winchester in white box labeled 7.62 just saw this post and grabbed some brass on the Dag I had the scuff mark didn't seem as wide hard to tell in relation to picture scuff was smooth to touch on some if scuff was held at 3:00 there was a little burr at not quite 4:00 not bad but you could feel it,from extractor grab I believe,on the winchester smaller scuff yet strong 16Th other was strong 8Th some winchester showed no mark and no burr was felt light lap was good idea,to you feel this is a problem with operation or on reload aspect?Looked at brass from RRA coyote and very slight scuff on very edge nothing as pronounced on .308 and no burr.I don't know much but am mechanical think it nature of the beast though its hard to tell the severity from one rifle to another.Now it's clear as mud, was nice to get out wish I knew how to send pics of targets, still working on basics breathing and not rushing the shot but I try to shoot quicker and more accurate[i know I'm running before I can walk].I'm also computer illiterate but trying.Shoot on bro.

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