Barrel nut touching receiver on new upper assembly

spotstalkshoot

spotstalkshoot

Well-known member
My new BHW 20 practical barrel came in last week. I now had everything to assemble for a new night hunting rifle. I never loaded a "wildcat" before, started with 24.5 grs Benchmark and some 32 gr vmax seconds. Initial shoot/clean sequence was very promising 1/2" or smaller groups, cleaning between not changing poi enough to open groups. Made up some other test loads, shot some at 185 yards over the weekend and noticed some vertical dispersion. Went back to 100 yards with some more of original loads, now I have 3" and more vertical. Well I pulled hand guard and barrel nut, barrel nut when torqued is against upper, measuring I have about 0.01 interference. I believe this is my issue with the change of poi and vertical stringing, through the three range visits(slow fire load testing). Have I found the issue ?
 
remove the nut and see if it is actually contacting the receiver and to what degree. Always contact the manufacturers involved first.
 
I removed the nut, barrel extension ring to receiver side of nut edge is .753 inches, there is .653 inches of thread on the bottom(hinge side) of receiver. Should I take 0.015 off the barrel nut, receiver side? Or shim between Barrel extension and nut? Freefloat handguard is a Lantac spada-s, Anderson upper.
 
measure another known quality receiver, or call BHW for advice, they are good to work with. Also the maker of the receiver could be helpful. First guess would be the receiver, just a guess from what you are saying.
 
Typed incorrect measurements, barrel nut .575-0.578 when checked at 4 points. Barrel extension to receiver face is 0.558- 0.561 so most contact is in the hinge area of the upper.
 
Did you happen to look to see if the gas block is hitting the hand guard mine would do that and I had problems. I was able to shim the base of the hand guard to hold it away from the gas block.
 
Not sure if I measured mine the same. I have a new Spikes upper. I put the barrel in it. Measuring from top of flange on the extension to face of receiver, I have .577 and just measuring from the front of the threads to receiver face is .542
 
Gas block is clear,sits just in front of the 12.5" guard. Sent email to Anderson just to check on the receiver numbers. I had bedded the barrel with red loctite(271) so had to heat gun the barrel to remove. Just nowhere near me for some shims, leaning towards having my local smith take 0.02 off the receiver side of the barrel nut that would give me 0.005 ish clearance. Reb8600 I would be gtg if I had .580 from muzzle side of flange to receiver. I will probably email Lantac also.
 
Update, heard from Anderson, said You may have to shim. Nothing but auto email from Lantac saying could be a couple days. My smith chucked it up and took 0.027 off the receiver end of barrel nut. I cleaned everything and assembled again. Made up some loads, will shoot again. Hoping 10$ for the machining fixes the fail to repeat groups issue.
 
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Originally Posted By: spotstalkshootUpdate, heard from Anderson, said You may have to shim. Nothing but auto email from Lantac saying could be a couple days. My smith chucked it up and took 0.027 off the receiver end of barrel nut. I cleaned everything and assembled again. Made up some loads, will shoot again. Hoping 10$ for the machining fixes the fail to repeat groups issue.

I have put the barrel nut in a vise and filed .010 to .015 off and it always worked for me.
 
Originally Posted By: 1lessdog
spotstalkshoot said:
Update, heard from Anderson, said You may have to shim. Nothing but auto email from Lantac saying could be a couple days. My smith chucked it up and took 0.027 off the receiver end of barrel nut. I cleaned everything and assembled again. Made up some loads, will shoot again. Hoping 10$ for the machining fixes the fail to repeat groups issue.

I have put the barrel nut in a vise and filed .010 to .015 off and it always worked for me. [/quote}

Or Sandpaper on a wood block
Click to expand...
 
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