Im almost done with an ar build, it's an aero prescison complete factory assembled upper, and going to use a Aim surplus v2 nitrated bcg. I've read you need to check head space, then seen many people say just slap it together and shoot it. It's all new stuff, so any advice? This is the first non complete rifle I've had. If I need too check it, how do I do it?
Is it nessecary?
- Thread starter jwill130
- Start date
Any smith can check it, or you can buy the tool.
The tool is a couple of cartridge shaped pieces. One is the shape of a perfect length 223 cartridge; the other piece is just a tiny bit too long to be a 223 cartrigde.
The idea is:
If both fit in your chamber, the headspace is too long. If only the shorter one (labeled "Go") fits, your chamber is in spec. If neither fit, your headspace is too tight.
By "fit", I mean to say the the bolt closes fully or moves fully into battery.
AR's from quality parts benefit from CNC milling. Parts are generally interchangeable. This is not the case with most firearms.
The proper thing to do is to check the head space. I would just ask a Pro to do it, they might catch a problem for you and save you money in the long run.
If you decide not to have it checked, shoot some factory ammo, one round in the mag at a time, collect the empty brass and measure it--before you clean and resize for reloading. Then you can see if it grew. If so, your head space might be too long.
I had an old rifle that I could only reload ammo once for each case. The head space was off, and the brass would stretch, causing it to fail just above the rim (257 Roberts). I had it re-barreled.
The tool is a couple of cartridge shaped pieces. One is the shape of a perfect length 223 cartridge; the other piece is just a tiny bit too long to be a 223 cartrigde.
The idea is:
If both fit in your chamber, the headspace is too long. If only the shorter one (labeled "Go") fits, your chamber is in spec. If neither fit, your headspace is too tight.
By "fit", I mean to say the the bolt closes fully or moves fully into battery.
AR's from quality parts benefit from CNC milling. Parts are generally interchangeable. This is not the case with most firearms.
The proper thing to do is to check the head space. I would just ask a Pro to do it, they might catch a problem for you and save you money in the long run.
If you decide not to have it checked, shoot some factory ammo, one round in the mag at a time, collect the empty brass and measure it--before you clean and resize for reloading. Then you can see if it grew. If so, your head space might be too long.
I had an old rifle that I could only reload ammo once for each case. The head space was off, and the brass would stretch, causing it to fail just above the rim (257 Roberts). I had it re-barreled.
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There are a couple of old threads about checking headspace on an AR build.
It's a factory built new upper; is it a new BCG? If so you should be fine.
I have a few AR's, including a couple of uppers I put together myself. I use parts sourced from reputable dealers and have never checked headspace and have never had a problem.
It's a factory built new upper; is it a new BCG? If so you should be fine.
I have a few AR's, including a couple of uppers I put together myself. I use parts sourced from reputable dealers and have never checked headspace and have never had a problem.
Personally, I would not worry. How many people check the head space on a new complete factory rifle? Just because it's already pinned to a lower the upper is no different than the one you bought separately.
If the parts are of reputable quality and in spec, then you'll be good to go. If you cobble together the absolute cheapest parts that you can find, I'd take it to a good Smith or a shop that knows what headspace is and just let them check it for you.
I wouldn't worry about it with quality components.
A simple check: Chamber a round, remove the upper, you should be able to see if the barrel and bolt lugs have properly engaged by looking at just the right angle from the bottom of the receiver. If the lugs engage, you'll be fine. For the love of God don't somehow manage to blow a hole in your wall in the process.
A simple check: Chamber a round, remove the upper, you should be able to see if the barrel and bolt lugs have properly engaged by looking at just the right angle from the bottom of the receiver. If the lugs engage, you'll be fine. For the love of God don't somehow manage to blow a hole in your wall in the process.
You may just want to do some reading on the subject -- from a reputable gun smithing source.
All of the parts can fit together perfectly but the distance from the face of the bolt to the part of the chamber where the bullet case shoulder begins -- the bottleneck-- is the measurement you are checking on a bottle necked, non belted cartridge.
CNC's have helped standardize things, but if the bolt, barrel, and upper receiver are not from the same AR manufacturer, or at least from a U.S. Miitary Supplier, I would not trust it.
Would it hurt you if the head space is off? I am not sure one way or the other, the AR has a lot of safety features built into it. The brass may rupture, but I am not sure it would hurt you, particularly if you you and the gun are right handed models.
All of the parts can fit together perfectly but the distance from the face of the bolt to the part of the chamber where the bullet case shoulder begins -- the bottleneck-- is the measurement you are checking on a bottle necked, non belted cartridge.
CNC's have helped standardize things, but if the bolt, barrel, and upper receiver are not from the same AR manufacturer, or at least from a U.S. Miitary Supplier, I would not trust it.
Would it hurt you if the head space is off? I am not sure one way or the other, the AR has a lot of safety features built into it. The brass may rupture, but I am not sure it would hurt you, particularly if you you and the gun are right handed models.
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He said it's a factory built new upper & a new BCG, not something somebody hammered together in their garage.
Should I check the headspace on every rifle I buy? Do you?
Nice visual aid though.
Should I check the headspace on every rifle I buy? Do you?
Nice visual aid though.
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