Lilja Short Barrel... New Poll

[Kikn]

So that is a no to everything else that isn't upper and hand guard, like the gas block?

[cory]

That is correct. The deal I got I'm paying for out of pocket for a large order within the week. I'm going to buy enough to cover the group buy plus a few. If I have any left over, I'll sell them at a discount, but not the same discount the group buy members are getting.

[cory]

I was thinking, some may not have the tools to assemble an upper or a set of crow wrenches sitting around. I haven't asked, but I'm a pretty confident we could add some of Spike's Tools to the order at the 20% discount.

http://www.spikestactical.com/tools-c-145_161.html

If there's something you want just include it in the email with your spreadsheet. If you've already emailed me, just shoot me another quick email with what you want.

On that note I could probably get a few of SLR's 2mm ball drivers.

http://slrrifleworks.com/index.php?route=product/category&path=57&page=2

If you're interested in one of these with your order I'll need to know that by Wednesday.

[cory]

I need to get a good count on who's in on this email, what everyone's preferences are and what other deals they'll be getting in on.

Please download the excel sheet at the following link and then email it to me at me.cory.m.clark@gmail.com (the email is correct, please copy and paste)

https://www.dropbox.com/s/vp66x3vvs9qgf1z/Feel%20for%20Interest.xlsx

I've also posted the link in the OP.

Thanks

I need to get a count on who's interested. I need to make sure we have enough interest to place an order for barrels, then the slr and spike's deals. Right now I'm not showing enough interest.

If you could feel out the spreadsheet and get it back to me I'd appreciate it. I tried to make it as short and simple as possible.

[Adam Lilja]

Cory your inbox is full. My offhand guess for a fluted 740 is 2.5 lbs but we don't have any to weigh at the moment.

[cory]

Cory your inbox is full. My offhand guess for a fluted 740 is 2.5 lbs but we don't have any to weigh at the moment.

Cleared. 2.5lbs seems heavier than I'd think.

Does anybody have one that they have weighed or can weigh and can help us out?

[KentuckyBuddha]

I weighed one at 927.4 grams or 2.04457lb

the other was 926.6 grams or 2.0428 lb


Two and a half is a pretty good guess Adam!

[Variable]

Are we all talking apples to apples?

Their AR740 drawing shows 2.43 pounds for a 20" (actually 19.615" ATF length) 5.56 barrel. It is at least depicted in the drawing with the barrel extension installed also.

hows 2.43

[Variable]

I weighed one at 927.4 grams or 2.04457lb

the other was 926.6 grams or 2.0428 lb


Two and a half is a pretty good guess Adam!

Length? Fluted?

[KentuckyBuddha]

The question was a 740 fluted, and that just happened to be what I had two of on hand. : )

[cory]

Thanks Kentucky!

Here's my calculations


If anything the AR740s are a tad heavier than they'll come out to be since we'll go with 0.725" in front of the gas block as opposed to the 0.740". That being said we're talking about 0.2oz.

Edit: with Variables calculations it seems adding 1/2" for my calculations was to much. I should have added 0.375". My calculations should be on the heavy side.

[KentuckyBuddha]

Btw that was measured with a brand new out of the box Grobet digital scale which is supposed to have a .1 gram accuracy.

[cory]

Got News!

Talked to Dan and if we hit the 25 barrel mark and get at least 10 per we can go 2 different barrel lengths.

May the best 2 of 3 win. 10.5", 11.5", 12.5"

That being said all else will need to be identical.

Dan also mention they got a new lathe dedicated to AR barrels, so once we order them we should get the barrels a pretty quickly.

Variable was also kind enough to doing some measuring for us.

With Grendel barrels there appears to a difference of 0.375" in AFL barrel length and OAL barrel length.

[cory]

With Variables calculations it seems adding 1/2" for my calculations was to much. I should have added 0.375". My calculations should be on the heavy side.

[Variable]

Okay, I keep running my crazy scribbles all different ways, and I think you are probably close. I like shaving the barrel to .725" in front of the gas block journal, and quite frankly, I'd even vote to shave it to .725" under the handguard as well. That might sound thin to you, but remember--- this is a way shorter barrel. Shorter barrels become a great deal stiffer per inch.

Makes my head spin, but check here for some good barrel stiffness info: http://www.riflebarrels.com/articles...est_rifles.htm

This quote is pure gold: "For example, I found that a 24" heavy varmint barrel is 32% stiffer than a 26" version. A 22" HV barrel is about 35% stiffer than that 24" barrel and an 18" HV barrel is 98% stiffer than the 22" barrel. Remember the earlier statement about length being raised to the third power in the deflection equation? The 18" barrel is 3.51 times stiffer than the 26" barrel. Interesting?"

I know you guys want a stiff tube (who doesn't want their tube to be stiff!LOL), but you are in the overkill department IMO. The reason the other shorty barrels like the Sabre 10.5" Grendel are so thick is purely for heat absorption in my opinion. If you aren't doing full auto mag dumps, I think they are unnecessary overkill.


ETA: Had to tap out all the above at warp speed, because I was up against a hard break, and had to relocate.LOL Back to it---

If someone knows how to do all the math at that link (certainly not me), I'd be curious to know just how stiff a 12.5" barrel of .700" diameter would be compared to the 20" AR740 profile in the chart above. For giggles and grins, how about a 12.5" barrel at .680" diameter against the 20" AR740 profile.

It may be entirely possible to crank out a stiffer barrel than the 20" AR740, while under 20 ounces (with barrel extension) without even resorting to fluting. That'd save 115 bucks and make me mighty happy.LOL

The original 20" M16A1 profile was .625" both fore and aft of the gas block journal, and was plenty stiff enough for non-extreme use. I've seen plenty of accurate examples in the past. If a .264 version were shortened to 12.5" and bumped up to .680" (or thereabouts) it'd be pretty darn stiff. It also wouldn't bend when opening the imaginary ration crates!LOL http://www.ar15.com/forums/t_3_12/57...age=1#i5514553

What I'm getting at in a roundabout way is that I think a short barrel could be had that would appeal to the lightweight crowd, while actually being even stiffer than a 20" .750 diameter barrel. It wouldn't be as massive of a heat sink, but even I'm not crazy enough to pay for a Lilja barrel and then start cranking it for full auto mag dumps.

Hopefully my ramblings make sense. I'm on one of my perpetual sleep deprivation benders while constantly being distracted and interrupted on my end at the same time.LOL