I dont have a set of headspace gages and I havent even been able to find a matching brand in stock anywhere. I should have my barrel in hand next week to make with the BCG I have. I am told that I can check headspace with a quality nato round and .003" "GO" then .005" "NO-GO" shim stocks cut to fit inside the bolt face. I am fairly sure that this is a fine practice for building a safe rifle. I am building a accurate rifle (I hope). I am in Vineland if anyone wants to loan,rent,sell a set of gages for 5.56

How much will headspace effect accuracy as long as its within safe limits?

If you are not attaching the barrel to the barrel extension you probably don't need head space gauges.There are probably a million rifles or so out there built without them.

Vlad G- I agree with you 100% about rifles being built in that manner.

But, im a machinist and precision is important to me. As far as safe firing I have been told by a smith that I can use a 5.56 cartridge and .003 and .006" shim stock for go no/go respectively. That should get me shooting and then I can work on pulling in the accuracy of the gun if need be.

If your really care that much, Brownells sells the Clymer go/no-go 5.56 gauges (184-000-036WB and 184-000-035WB) they'll run you about $80 together. 

 

If you buy your components from reasonable places and buy milspec bolts, and chambers that are actually chambered for what they say they are  (as opposed to being done with worn reamers) then you really don't a worry. On the accuracy front, if you want maximum accuracy you need to handload anyway, which means you effectively set your own headspace 

 

If this is something that really concerns you, buy a matched barrel and bolt that were fitted together at the "factory". 

OP - If you just send me a fired case (Brass Please)  I can guage it and give you a good idea of what's going on.

look on ebay for forster gauges.

 

http://www.forsterproducts.com/categoryShopping.asp?category=22919&catid=19938

 

you only need min/max gauges if you are headspacing for 5.56

OP - If you just send me a fired case (Brass Please)  I can guage it and give you a good idea of what's going on.

Thank you for the generous offer. I just got the thing together last night using the shim stock and a LC Nato cartridge for headspace. I need to find a few minutes to get to a range and see what it will do. I dont expect cycle or safety issues. My only concern is accuracy. I figure I wont know until I get about 100rnds down the pipe. I will post up a pic or 2 on the "show us your AR thread"

You don't need a go gauge unless you are reaming a chamber. For your Lego project, just get a field gauge. Forster work good