The Chart for ar 10?

[orionz06]

I have heard HPT compared to driving a car into a wall to test the bumper. I'm not sure I buy that comparison, or the idea that it necessarily shortens the life of the part.

It is along the right idea, think of it more as having the fat kid climb into the tree house first. If it works for him, it works for the rest. I am also under the assumption that a failure during HPT was more so due to flaws in the bolt, not the load applied from the HPT. I have been trying to create an FEA model to see how the stress is distributed through the bolt but my time at work for that has been limited.

[MistWolf]

It wouldn't be that hard to chart the differences & similarities of the various AR308s.

One important item would be magazines. Most use the KAC pattern, at least three use the Armalite pattern, one uses Fal mags and I believe one uses G3 mags.

Another is receiver material. While the majority use 7075 aluminum alloy, Armalite uses 7175 which is a bit tougher than 7075. The chart can show whether the receivers are forged or billet and which uppers are compatible with which lowers.

Barrel material. What alloy steel or stainless steel is used. Weapon weight. If small parts are forged, cast or MIM. Rifle configuration. It could also show proprietary parts and special features.

You don't need a milspec to create a comparison chart of rifles

[KevinB]

FYI only the M110 SASS from our 7.62mm guns gets HPT and MP'd

The M110 Bolt life is around 7,500 rds. The rest of the Mk11's, and SR-25's are not HPT'd and have bolt life in excess of 12k -- I've seen some 17k + bolts.

FYI Canada only has about 24 AR10T's, hardly what I would call an adopted amount, they where bought on an Immediate Operational Requirement, and had to have 24" barrels . They will be doing a SASS and SharpShooter program within the next two years.

[kartoffel]

it's not likely to happen due for the most part to the lack of a military specification for AR10s.

Makes sense. By the way, thanks for making The Chart! It's an invaluable resource. It might be possible to do multiple AR-10 charts, say, one versus the L129A1, another versus M110. Then you'd run into the problem of figuring out which of those competing versions is "better".

Wanting to make a chart for AR-10's highlights a problem I've seen with people mis-applying The Chart, i.e. comparing something that's not a 5.56-shooting, 14.5" barrel, carbine length DI gas weapon to The Chart and then claiming that the compared weapon is not "good enough". Maybe it isn't good enough, but an apples-to-oranges comparison is flawed to begin with.

[rob_s]

You don't need a milspec to create a comparison chart of rifles

Clearly, but then there is no standard to which the various rifles are compared. Nothing wrong with that, but it just wasn't the original intent of the existing M4 Chart.

[KevinB]

FYI I think its possible to use the M110 and L129A1 in the same chart. There are more similarities than not.

Of course that chart then skews data in favor of KAC and LMT, but I am okay with that

[500grains]

Knights (US)

LMT (UK)

That was easy lol

How about Noveske and Larue in .308?

[rsilvers]

I'm not sure where this idea that no parts are ever rejected in the MPI process came from.

Of those who you have info from - what percent of parts gets rejected due to MPI?

I find it hard to believe Colt has a 20% scrap rate on machined bolts and barrels. I have heard that cast parts can have up to a 20% reject rate.

[rsilvers]

Proofing an established design is not really worth it. Test firing for function is more important.

I strongly believe in gauging parts for conformance to the drawing. I am all about that. It makes baby jesus cry to make parts which are out of print.

But there is no way to chart this. There is no way to really know how good each company is with regard to in-spec parts unless you buy a lot of each of them and check them.

[Iraqgunz]

I think I heard that number as well. It's not like they want do it, they have to do it because of outside inspections and QA.

ON a different note when a manufacturer claims that they haven't rejected any I get a case of the BS blues.

Of those who you have info from - what percent of parts gets rejected due to MPI?

I find it hard to believe Colt has a 20% scrap rate on machined bolts and barrels. I have heard that cast parts can have up to a 20% reject rate.