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Post by blamm1009 on Nov 1, 2016 11:48:50 GMT -8
Ok, I will look into that. Again, the rounds are feeding just fine during firing and extracting rounds from the chamber is much easier now too.
On the firing pin though, it is a different issue. The firing pin is the exact same length and dimensions as my other ar15 pins. The excess protrusion is there with 4 different pins I have put in it. The bolt itself is actually shorter on the back end which allows a standard pin to protrude further. Must be cheaper or easier to make the bolt 0.030 shorter than buy enhanced firing pins. I might need to shorten the firing pin 0.015" or something, but for the most part it doesn't seem to be causing a problem so I will most likely just leave it be unless it starts causing issues.
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Post by GLSHOOTER on Nov 1, 2016 12:34:01 GMT -8
Ok, I will look into that. Again, the rounds are feeding just fine during firing and extracting rounds from the chamber is much easier now too. On the firing pin though, it is a different issue. The firing pin is the exact same length and dimensions as my other ar15 pins. The excess protrusion is there with 4 different pins I have put in it. The bolt itself is actually shorter on the back end which allows a standard pin to protrude further. Must be cheaper or easier to make the bolt 0.030 shorter than buy enhanced firing pins. I might need to shorten the firing pin 0.015" or something, but for the most part it doesn't seem to be causing a problem so I will most likely just leave it be unless it starts causing issues. The tail cut is the easy way for a manufacturer to use standard pis. The enhanced pins have the collar moved. One can take a standard length 264 bolt and then turn the inside of the collar down using a drill and file to get more protrusion. You could take a tad off the pin tip if you wanted to. Easy does it though. Greg |
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Post by philoaz on Nov 26, 2016 22:18:48 GMT -8
Hi all.
I am new to the forum but not new to reloading or building custom rifles. I recently order a .243LBC barrel and a .458SOCOM barrel and thought I would start looking at load data while waiting on the barrels and came across this thread. I am pretty sure your cratering issue is from an undersized firing pin, an oversized firing pin hole or both. I have been loading for ARs for 25 years now and never needed to use the milspec primers. If its a good bolt and the rifle is properly set up you wont need them. There are several great sources for quality bolts that will solve this issue. JP Enterprises sells a matched set of the chromium nitride bolt, firing pin, cam pin, and retainer pin. It is a Type 1 bolt with .125" face depth. Alexander Arms sells a good bolt for less but it is a type2 with a .136" face depth. Maxim Firearms sells both type 1 and type 2 bolts and even supplies their bolts to many AR manufacturers. I forgot to ask last week when I ordered the barrel what they chamber there barrels for but will call next week to be sure. Going cheap with this type of cartridge is not advisable, especially if you plan to compete with the rifle. I have seen bolts break with 6.5G rifles and ruin a good day. Think parts of your bolt falling out the mag port when you drop the mag to clear the rifle or falling into the trigger well.
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Post by GLSHOOTER on Nov 27, 2016 6:30:51 GMT -8
Welcome to the board. The chamber on your rifle will be Type I. The LBC is a great cartidge for fun and games. I shoot it in F-Class as my main cartridge choice.
Between Ritch and I we have shot literally thousands of rounds with the TYPE 1 bolts in a dozen rifles or so. Never have broken a bolt yet. Of course if you load sanely it is a non-issue. With the new dedicated bolt face bolts vs. being opened up they are much stronger and 9310 steel is very good for the longevity in our experience. I've seen bolt broken on 223, 6.8, Grendel and LBC from various manufacturers. The main issue we have seen over the years was an occasional bad heat treatment and guys that could break a bowling ball in five minutes..
Greg
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Post by philoaz on Nov 27, 2016 9:07:28 GMT -8
Thanks for the info on the chamber type for the barrel. I ordered it as I wanted to experiment a little now that my current Lilja Grendel barrel (my second in this rifle) is getting a little long in the tooth. I personally have only had one broken bolt and that was 12 years ago in my original Colt A1 which had around 12,000 rounds through it. I was just on the verge of replacing the barrel again so it was replaced as well. I have seen a handful break at NM matches and surprisingly saw a 6.5 Creedmoor LR-308 broken bolt at the range a few weeks back. It broke back at the ejector pin. That was a lot of metal to break.
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