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My HK91 Bolt-Gap is out of Spec. Which Rollers to Order?
2/26/2012 4:46:06 PM
I have an early 80’s near new condition HK91 (IB date code) that I have owned since new. Along the way I ended up with a complete spare bolt carrier w/ bolt-head.
Today I was reading about how important it is to check bolt-gap and that it should be between .012 and .020. So I checked it for both bolt carrier assemblies. One complete assembly has a .011 bolt-gap and the other complete assembly has a .009 gap. If I swap locking pieces the gap measurement swaps between assemblies (gap follows locking piece). I find this strange because this gun only has fired about 2000 rounds since new. Oh well. The measurements don’t lie.
So I need to order new rollers for both bolt-heads. Given these bolt-gap measurements (.009 and .011), which number rollers should I order for each bolt-head? I assume I want to get as close to being slightly under .020 as possible, correct? Do I need any other replacement parts to do the roller job other than the 2 rollers?
Many thanks for any advice you can offer.
UPDATE:
Someone made me aware that HK lists the bolt-gap spec in the G3 Armorer's Manual as .004" to .020". It turns out the .012" to .020" spec listed on other webpages/forums is incorrect. My bolt-gap is within the spec after all. See below from G3 Armorer's Manual:
Today I was reading about how important it is to check bolt-gap and that it should be between .012 and .020. So I checked it for both bolt carrier assemblies. One complete assembly has a .011 bolt-gap and the other complete assembly has a .009 gap. If I swap locking pieces the gap measurement swaps between assemblies (gap follows locking piece). I find this strange because this gun only has fired about 2000 rounds since new. Oh well. The measurements don’t lie.
So I need to order new rollers for both bolt-heads. Given these bolt-gap measurements (.009 and .011), which number rollers should I order for each bolt-head? I assume I want to get as close to being slightly under .020 as possible, correct? Do I need any other replacement parts to do the roller job other than the 2 rollers?
Many thanks for any advice you can offer.
UPDATE:
Someone made me aware that HK lists the bolt-gap spec in the G3 Armorer's Manual as .004" to .020". It turns out the .012" to .020" spec listed on other webpages/forums is incorrect. My bolt-gap is within the spec after all. See below from G3 Armorer's Manual:
2/26/2012 4:49:56 PM
I would get some +4 rollers, Hk 91 parts are cheap. You can also get G3 Locking pieces pretty cheap as well.
2/28/2012 11:43:02 AM
+4 rolllers and have +6 rollers for latter
2/28/2012 1:45:16 PM
UPDATE:
Someone made me aware that HK lists the bolt-gap spec in the G3 Armorer's Manual as .004" to .020". It turns out the .012" to .020" spec listed on other webpages/forums is incorrect. My bolt-gap is within the spec after all. See below from G3 Armorer's Manual:
2/29/2012 2:14:03 AM
Jeff Walther's aka ghiliabear told me that if you run under 12 you wear and tear goes up a bit faster the closer you get to 18 is Ideal
also your recoil will be less with some +4 rollers
my sar8 over stamp was 9 or 10 for ever I added +4 like Jeff told me and recoil is 50% less
there a reason 18 is Ideal
also your recoil will be less with some +4 rollers
my sar8 over stamp was 9 or 10 for ever I added +4 like Jeff told me and recoil is 50% less
there a reason 18 is Ideal
