Here we go....

14.5 inch Diemaco barrel as a base. shooting S&B, USA, Federal white box and SA PMP.

fatboy gas tube, LMT SOPMOD 2 bolt carrier(heavier) and 9mm buffer-----Works good on USA and Federal ammo, no workie with S&B and PMP. very low recoil.

Fatboy with regular carrier and 9mm buffer, work with all ammo.

Regualr gas tube with LMT and 9mm buffer, works with USA, Federal, and PMP, problems with S&B

Regular gas tube and carrier with 9mm buffer works on all ammo.

Fatboy with H stamped buffer and LMT carrier, works with all except S&B

Fatboy with regualr carrier and H buffer works on all ammo

fatboy with regualr carrier and standard buffer, works on all ammo.

regular everything took all ammo. with noticeable increase in recoil against the fatboy, LMT and 9mm buffer.  this setup is almost like shooting a 22mag.  pretty freaking cool

You can notice the S&B ammo is under power especially shooting against the
Federal white box.

I don't know if all this info is relevant, but I figure I post it to bring up my count. :)

Great info SMGLee! You always come up with interesting things. Now where is that pic of the new Battlegrip fore grip? LOL!

Nice info.

What about a dirty test?  Say a case of each ammo?   Hahaha, that would be something?  No telling where/who you got the barrel?

Since it is recoiling so lightly, is there a chance that it is [b]free floating[/b]?  I doubt it, but it is probably hitting the back of the buffer tube at a significantly slower pace.

Really nice info!

Thanks guys, I figure someone might make use of this info when they are setting up an upper.  or I just added a post to my count. [:)]




The picture is posted at the rifle, upper section.  

[img]http://www.thermaldynamics.com/pictures/td/tdfg001.jpg[/img]

SMGLee, great info and of specific concern to me as I use some of those combo's and noticed some didn't work.

Next question - what was the rate of fire for each set up?  Could I send you one of Black Rifle Armory's new SOCOM (or whatever buffer) for testing?  This is the buffer with the spring loaded tip that reduces ROF and felt recoil.  I have some problems using it with a Fat Boy gas tube in 11.5" setups.  I would be currious as to the same combo information using this buffer, the Fat Boy, and any other component and setup.  I won't have access to it for another two months, but I would be willing to send it to you.  Also have an adjustable carbine gas tube I was going to sell (from Brownells by Armforte MFG) that I could send now if you would like to play with it to see if that corrects problems.

P.S. hey, where did you get that front Battlegrip?

What was the recoil like with that combo Lee?

I love any excuse to go to the range, if you like for me to test it with the buffer, I would be honored to do a test and post a review.  Please e-mail me for my shipping address.  

The owners at TD are good friends, I just happen to walk in that day while they were fitting the first batch for shippment to Crane.




Lumpy,

The recoil is like a reduced or cheap reload 223. I think this is as close to the feel as I can explain it.  Hope this gives you an idea.

Thanks for the info SMGLee.  I had just been wondering if those combos would allow for 100% function or not... very nice breakdown.

Would opening up the gas port slightly reduce some of the failures w/ the lower-powered cartridges? I've considered, among other things, config'ing an upper w/ a Fatboy, LMT/KAC/other carrier (assuming it becomes a mass-market item) & increasing the gas port slightly to 0.091" on a 14.5" bbl. Either a heavy, or even a pneumatic (if they work) would be the buffer of choice.

Any thoughts, Lee?

A pneumatic buffer would work, assuming that in failure mode, it was heavy enough to work decent.

What about a variable rate spring?

Now try Putting Mcfarland gas rings into the equation.  I had problems with the FatBoy/H Buffer and Mcfarland rings. If I took out any one of the three the my Bushmaster 16 inch would run when clean.  After alot of shooting I decided my weapom would go longer dirty with a stock gas system.  I quit using all three of the above "improvements".  The fat boy did reduce recoil but at the cost of reliability.  Now the only mod I use is a SAW heavy extracter spring.  I am at 1260 rounds of Q3131a and xm193 plus some black hills 69 grn without a FTF. With other parts in the weapon it would start to short stroke at 300 or 400 rounds.

Strange as it may seem, the mcfarland gas rings caused short stroking.  They are designed to prevent gas blow by and the short stroking it causes.  I think they just made the bolt to carrier fit too tight.

I have spent a bunch of money on just about every reliability mod out there (exept the new LMT stuff) and I can tell you that, unless you are just tying to reduce recoil or change ROF, you are better off with a stock mil spec weapon with good GI mags and Q3131a or xm193.

Inkaybee,

I have McFarland gas ring in all my bolts.

How often do you clean and lube?  Try going 1000 rounds w/out cleaning and only minimal lube.  I'll bet as your weapon fouls it will start to short stroke.  I didn't believe it either until Dano over on the trouble shooting forum set me straight, now my 16" preban Bush Master is 100%.  Then again, it seems like every weapon has its own "personality" and what works for one does not always work for others.  My Colt 20" preban has always been 100% reliable in its stock configuration.

Ok, I can swear that some of the posts that are dated before mine, were not there before I posted.  Some sort of uncommon lag in the board?  And they are all dated several hours before so that seems strange.

Ok, someone said that the McFarland gas rings seemed tighter than stock 3 rings on the carrier/bolt relationship.  Wouldn't this wear in like any other sealing ring?  Maybe you should put it back in, but don't oil it there?

SMG Lee, I am ASSuming that you put the MacFarland ring in and never had any problems?

Thanks!