AR-10 Rifle vs. M1A Springfield Armory .308

[Bart B.]

What's worse, fake expert mode or fake preaching counter mode.

All the mechanical engineers professionally employed in vibration analysis say anything that touches a vibrating beam will make its fundamental and resonant frequencies change. The reason is more mass is added at that point to the major vibrating element.

How's that for a fake expert moding away intelligently?

 

[RX-79G]

I never claimed that. You're confused.

You said this in a thread about two gas operated rifles:

It has nothing to do with the barrel touching the gas block or gas tube, since holding the rifle doesn't put force on those parts.

Neither rifle can be completely "free floated", because the term does not just mean that the stock isn't putting pressure on the barrel. I don't know why pointing that out earned your rude response, but both rifles maintain a mechanical connection between barrel and receiver that can have an effect on the free movement of the barrel. That includes the harmonics Bob mentions.

 

[Llama Bob]

Bart, you're confused. The point of free floating is to keep pressure on the stock/forearm from changing point of impact relative to point of aim. Gas blocks have nothing to do with that.

Now, anything you attach to the barrel (e.g. a muzzle device) changes it's vibration by virtue of changing the mass, but that HAS NOTHING TO DO WITH FREE FLOATING.

Seriously, you need to get in learning mode ASAP. This is embarrassing for you.

 

[Llama Bob]

You said this in a thread about two gas operated rifles:


Neither rifle can be completely "free floated", because the term does not just mean that the stock isn't putting pressure on the barrel. I don't know why pointing that out earned your rude response, but both rifles maintain a mechanical connection between barrel and receiver that can have an effect on the free movement of the barrel. That includes the harmonics Bob mentions.

I'm still waiting for you to find where I said the M1A could be free floated, or to apologize for lying about what I said. Which will it be?

 

[RX-79G]

I'm still waiting for you to find where I said the M1A could be free floated, or to apologize for lying about what I said. Which will it be?

Okay, you did not specify the M1A, you said and continue to say that gas systems have nothing to do with free floating. So "I'm sorry".

Now that we're done with that, your initial rude response to my post was saying that I "admitted" the AR is free floated.

So now you have to admit the AR design IS IN FACT FREE FLOATED since there is nothing putting pressure on the barrel. Got it.

Please apologize to me for putting those words in my mouth, then cite a reference that says that gas tube contact counts as "free float".

 

[Bart B.]

Whatever pleases you, Llama Bob, is fine with me.

But I, as well as those 'smiths who rebuilt the very first M16 rifles allowed to be shot in DCM/CMP competition back in 1971, think otherwise. They were concerned about the gas system's attachment to the barrels causing accuracy problems as it was different than that of the M1 and M14 systems

 

[Llama Bob]

And they were wrong.

 

[Varminterror]

This is embarrassing for you.

From where I sit, you have this backwards.

You continue argue free floating only applies to the forend. If that were the case, it wouldn't be called "free floating," it'd be called "remove forend contact." Which is a different yet similar gunsmithing practice.

And they were wrong.

They're not - you are. The gas tube is not freely suspended in space, it does contact the receiver and BCG/gas key. A lot of factors come into play for how that contact affects the barrel harmonics - change your load, or buffer spring, or BCG weight, etc and your gas system behaves very differently. Heck, even if you just get a lot of gunk built up in your gas key you'll get different contact pressure against the gas tube - and subsequently also against the gas block, and of course, ultimately, your barrel. Equally, you have different pressure on the end of the tube when you take a cold bore shot than you do on your 10th round in a string as the tube warms up. Some people (and I'm not one of them), DO shoot well enough to see the difference in their POI.

Standing up on the fact that the forend pressure won't affect barrel harmonics in a "free floated" and insisting it's the same paradigm as free floating a non-gas operated rifle is silly. No, holding the rifle differently won't change the pressure I apply to the gas tube, so it gains an advantage by having less variable contact to the barrel, but it's not truly free floated.

I HAVE seen truly free floating AR's on match firing lines in the past - custom barrels with no gas ports, effectively operated as bolt action rifles. The ONLY reason guys ever do this (when match rules allow), is to eliminate the effect of the gas system contact on their barrel harmonics. Been several years since I've seen one, largely since most competition rules require the gas system in AR's to be operational as designed, preventing this modification.

You hear the same thing in specialty pistol forums all the time - guys talk about floating Encores & Contenders... They, like a "floated" AR, might be "as free-floated as their design can be," but they're not truly free floating. Ruger No.1 guys say the same thing, heck, I've even heard levergun and Marlin 60 guys talk about floating their barrels - when they have a mag tube dovetailed to the barrel!!

In the vernacular, people don't say "as free floated as the design can be," they just say "it's free floating." For a great number of models, it's NOT free floating when only the forend contact is removed.

 

[Llama Bob]

You're simply wrong. It does not touch the stock. It is free floated. Bolting things on the barrel (like sights, gas blocks, muzzle devices etc.) never had anything to do with free floating. The entire firearms industry, not to mention the engineering, agrees with me on this. Only a few clowns on a forum want to argue the other side.

Maybe you and Bart could hold little Ignorants Anaonymous meetings or something.

 

[RX-79G]

Bolting things on the barrel (like sights, gas blocks, muzzle devices etc.) never had anything to do with free floating.

Because bolting a sight that touches the barrel and only the barrel is different than making a mechanical connection between the barrel at the gas block and back at the receiver like a gas tube. The sight is going to move along with the barrel and share its harmonics.

The impact of this contact is variable - the AR gas system is going to affect the barrel less as it heats than a Stoner 63 gas tube, but that is a matter of degree. The extremely short Benelli gas system could be said to be free float system, but that's pretty much the only free floated gas system. Automatic fully free floated barrels generally have to be something like the HK91 where the barrel truly touches nothing after it exits the receiver.

 

[Rockrivr1]

I own a Rock River LAR8 (AR10 Clone) and a SA M1A Loaded. Both have their advantages, but I have to say that I enjoy shooting the M1A a tad bit more then the LAR8. I can't really say why as both are equally as accurate. The M1A just seems to fit me better. Though I would be hard pressed to keep one over the other.

 

[Art Eatman]

More than enough off-topic hostility.