New LRB Arms M14 Bolt> Report Update
This is the news that everyone has been waiting for, an evaluation of LRB Arms new M14 bolt. It's important to recognize that the bolt tested is a prototype and not typical. Some faults were found, but any deficiencies will be corrected in actual production.
I am pleased with the results and happy to find that LRB Arms is still intent on producing high quality parts for all of us gun nuts.
Notes on LRB Arms M14 Prototype Bolt
In early August, Lou Biancospino of LRB Arms called to inform me he was sending one of three new prototype M14 bolts for my inspection and evaluation. The three were produced from part of the original group shown at the 2010 SHOT Show in Las Vegas. Of the three, one was being sent to me, one to another company, and one was to be built into a rifle for testing by LRB after which it would be destructive tested by an independent laboratory. Lou stated that he wants to insure that the bolts meet government specs and destructive testing is the best way to accomplish it.
I received the bolt on August 18, 2010 with a note from Lou stating that this was the third attempt at making a bolt. “Still needs a few cosmetic changes as highlighted in red (color marker on bolt) but it works. Bolt is heat treated but needs phosphate. Includes roller - don’t have a retaining clip - sorry.”
I gave it an initial visual inspection as soon as I took it out of the box. The bolt had a brownish color probably due to surface oxidation. The overall appearance was good. I noticed six Rockwell hardness test dimples, four on the bottom and two on the top of the bolt body.
While comparing it with a GI Springfield Armory and TRW bolt I noted that the edges did not have as much radius as original issue bolts, but that didn’t detract from it’s overall appearance or functioning.
The supplied roller was a take off from another bolt and still had the remainder of it’s retainer in place. After the retainer was removed, I found the roller would not fit over the roller lug without binding and could not rotate so it was unusable.
Cosmetic changes indicated by the red marker were a little more than cosmetic in that they are areas that were not machined exactly to the drawing specs. However, they did not effect the functioning of the bolt in any way. The only exception was an area that requires undercuts at the rear of the lugs where they joined the bolts body. This causes the bolt to catch slightly when rotating to the locked position. Once in the locked position the bearing of the bolt lugs against the receivers recoil shoulders was as close as the government bolts used as a base line for comparison.
The receiver used for this test was LRB Arms M14SA serial number 02907. This receiver is from the latest production. It exhibits some roughness and machining marks within the bolt lug ways not usually found on most LRB receivers. I thought it would be a good example for the test as it may have some fitting issues that others would not. This turned out to be a misjudgment on my part as it assembled and functioned very well. The bolt traveled smoothly throughout it’s range in the receiver with the exception of the slight catch on closing previously mentioned.
Critical dimensions were checked with a micrometer and found to be within specifications. The radius at the front bottom of the left lug was sharper than specified, but did not cause any problems.
After bead blasting, the bolt was again inspected and no cracks or further problem areas were noted. There was a #9 engraved on the bottom left side of the bolt indicating it was the 9th bolt in the original batch. Lou indicated that only three of the original production bolts were completed for testing.
After bead blasting I finished the bolt with Orpho Blue from Brownell’s which gave it an almost Parkerized appearing black finish. I then installed a new bolt roller which fit and functioned perfectly.
I found that three of the five chromed GI firing pins in my stock would not fit in the bolt without binding. This worried me some until I tried them in a new TRW bolt with the same results. I assembled the bolt using a new chrome tipped firing pin and other new GI parts. All functioned normally. The firing pin projection and intrusion were within specs on GI gages.
On August 23rd I used a small file to relieve the areas on the bolt lugs that were causing the bolt to catch when rotating closed. These were small areas and required very little effort to correct. I lapped the bolt lugs with 120 grit compound for about 1 ½ minutes to achieve 100% contact on the right lug and about 50% contact on the left lug. I’m lazy so I quit at that point. There is an ongoing problem with the contact of the left lug in LRB receivers. This is common in almost all of them and relates to the angle of the recoil shoulder which results in the bolt lug bearing on it’s outer edge rather than evenly across it’s surface. It isn’t a serious problem and only requires some lapping to eliminate. LRB tells me they are working on a cure, but it seems to be a machining glitch that is difficult to fix. I chose not to spend a lot of time altering this area so I could see if there were any other problems which result from it.
I installed a new Criterion chrome lined 18.5” barrel for the test and fitted it with a Smith Enterprise gas lock front sight and direct connect flash suppressor. The rest of the rifle was assembled with GI parts and installed in a GI fiberglass stock.
I test fired the rifle dry and had a few failures to feed. The problem was short cycling caused by misalignment of the gas port. I changed the gas lock which brought the ports into alignment and lubed everything. Test firing resulted in no repeated failures to feed, but there was one failure to fire due to the poor quality of the Pakistani ammunition used for the test.
On August 26th I took the rifle to the Jackson County Sport Park for further test firing and ran several magazines of ammunition through the gun. There were no failures of any kind. Accuracy was good considering the wonderful quality of Pakistan’s 7.62 NATO ammunition. This is machine gun ammo which had to be delinked prior to use. Accuracy was about minute of pie pan at 100 yards, but it was fun to shoot anyway.
The new LRB Arms M14 bolt functioned flawlessly and has an excellent appearance. At this time LRB Arms has not established a price for it’s new bolt, but is hopeful that initial production will commence within a couple of months. It looks like a winner and I am looking forward to using them in my future rifle projects.
By Ted Brown
Shooters Den
I am pleased with the results and happy to find that LRB Arms is still intent on producing high quality parts for all of us gun nuts.
Notes on LRB Arms M14 Prototype Bolt
In early August, Lou Biancospino of LRB Arms called to inform me he was sending one of three new prototype M14 bolts for my inspection and evaluation. The three were produced from part of the original group shown at the 2010 SHOT Show in Las Vegas. Of the three, one was being sent to me, one to another company, and one was to be built into a rifle for testing by LRB after which it would be destructive tested by an independent laboratory. Lou stated that he wants to insure that the bolts meet government specs and destructive testing is the best way to accomplish it.
I received the bolt on August 18, 2010 with a note from Lou stating that this was the third attempt at making a bolt. “Still needs a few cosmetic changes as highlighted in red (color marker on bolt) but it works. Bolt is heat treated but needs phosphate. Includes roller - don’t have a retaining clip - sorry.”
I gave it an initial visual inspection as soon as I took it out of the box. The bolt had a brownish color probably due to surface oxidation. The overall appearance was good. I noticed six Rockwell hardness test dimples, four on the bottom and two on the top of the bolt body.
While comparing it with a GI Springfield Armory and TRW bolt I noted that the edges did not have as much radius as original issue bolts, but that didn’t detract from it’s overall appearance or functioning.
The supplied roller was a take off from another bolt and still had the remainder of it’s retainer in place. After the retainer was removed, I found the roller would not fit over the roller lug without binding and could not rotate so it was unusable.
Cosmetic changes indicated by the red marker were a little more than cosmetic in that they are areas that were not machined exactly to the drawing specs. However, they did not effect the functioning of the bolt in any way. The only exception was an area that requires undercuts at the rear of the lugs where they joined the bolts body. This causes the bolt to catch slightly when rotating to the locked position. Once in the locked position the bearing of the bolt lugs against the receivers recoil shoulders was as close as the government bolts used as a base line for comparison.
The receiver used for this test was LRB Arms M14SA serial number 02907. This receiver is from the latest production. It exhibits some roughness and machining marks within the bolt lug ways not usually found on most LRB receivers. I thought it would be a good example for the test as it may have some fitting issues that others would not. This turned out to be a misjudgment on my part as it assembled and functioned very well. The bolt traveled smoothly throughout it’s range in the receiver with the exception of the slight catch on closing previously mentioned.
Critical dimensions were checked with a micrometer and found to be within specifications. The radius at the front bottom of the left lug was sharper than specified, but did not cause any problems.
After bead blasting, the bolt was again inspected and no cracks or further problem areas were noted. There was a #9 engraved on the bottom left side of the bolt indicating it was the 9th bolt in the original batch. Lou indicated that only three of the original production bolts were completed for testing.
After bead blasting I finished the bolt with Orpho Blue from Brownell’s which gave it an almost Parkerized appearing black finish. I then installed a new bolt roller which fit and functioned perfectly.
I found that three of the five chromed GI firing pins in my stock would not fit in the bolt without binding. This worried me some until I tried them in a new TRW bolt with the same results. I assembled the bolt using a new chrome tipped firing pin and other new GI parts. All functioned normally. The firing pin projection and intrusion were within specs on GI gages.
On August 23rd I used a small file to relieve the areas on the bolt lugs that were causing the bolt to catch when rotating closed. These were small areas and required very little effort to correct. I lapped the bolt lugs with 120 grit compound for about 1 ½ minutes to achieve 100% contact on the right lug and about 50% contact on the left lug. I’m lazy so I quit at that point. There is an ongoing problem with the contact of the left lug in LRB receivers. This is common in almost all of them and relates to the angle of the recoil shoulder which results in the bolt lug bearing on it’s outer edge rather than evenly across it’s surface. It isn’t a serious problem and only requires some lapping to eliminate. LRB tells me they are working on a cure, but it seems to be a machining glitch that is difficult to fix. I chose not to spend a lot of time altering this area so I could see if there were any other problems which result from it.
I installed a new Criterion chrome lined 18.5” barrel for the test and fitted it with a Smith Enterprise gas lock front sight and direct connect flash suppressor. The rest of the rifle was assembled with GI parts and installed in a GI fiberglass stock.
I test fired the rifle dry and had a few failures to feed. The problem was short cycling caused by misalignment of the gas port. I changed the gas lock which brought the ports into alignment and lubed everything. Test firing resulted in no repeated failures to feed, but there was one failure to fire due to the poor quality of the Pakistani ammunition used for the test.
On August 26th I took the rifle to the Jackson County Sport Park for further test firing and ran several magazines of ammunition through the gun. There were no failures of any kind. Accuracy was good considering the wonderful quality of Pakistan’s 7.62 NATO ammunition. This is machine gun ammo which had to be delinked prior to use. Accuracy was about minute of pie pan at 100 yards, but it was fun to shoot anyway.
The new LRB Arms M14 bolt functioned flawlessly and has an excellent appearance. At this time LRB Arms has not established a price for it’s new bolt, but is hopeful that initial production will commence within a couple of months. It looks like a winner and I am looking forward to using them in my future rifle projects.
By Ted Brown
Shooters Den
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