DPMS LR 308 Classic runs hot

[ripper51]

Put a closed free float tube, closed as in not vented along sides. Torqued barrel nut to 70ftlbs and gas tube aligned perfectly. Screwed on the free float tube (DPMS part by the way for rifle length) . Tightened it with strap wrench so it does not bind or loosen. Drilled hole in bottom center for sling swivel mount and mounted sling swivel with no problem.

Finally got tall front sight post where it needs to be for a 200yd zero. Fired 10 rounds at 200 yds from seated position no rest. All in 10 ring and probably would have been an inch group except for my 4th shot which was just out of group at 11 but still in ten X ring. Barrel was warm. Outside temp about 80, no wind.

Tried sitting position High Power rapid fire, first string of 2+8, 2nd string 2+8. Barrel and handguard/free float tube was hot enough it should have been glowing. Needed an over mitt.

Let it cool then shot 5+5. First five cloverleafed in the x ring, second five dragged down thru 5 ring.

Put rifle in a lead-sled on a bench and secured it. shot 5 more- cloverleaf; 5 more and 3 of the 5 went into 6 o'clock miss the other two looked like they dropped to rings with each shot. Guy next to me had the opinion the barrel was drooping due to the heat.<GRIN> After I stopped laughing, I explained Chrome moly barrels normally don't droop until after a couple of hundred continuous firings and they are glowing cherry red. Handguard/freefloat tube was sure hot.

Thought I'd let it cool for 30 minutes and fussed with my M1A. Came back to the Lr308 and decided to use some Powder Blast through the barrel from the chamber side to blow anything stuck in there out. Squirted some in and it immediately sizzled and evaporated. Barrel was still frying pan hot.

I just ordered a vented free float tube and hope it helps with cooling.

My question (at last) is has anyone experienced this? How the heck can I shoot NRA High Power if I need cooling vanes, a portable AC unit and oven mitts to handle this baby?

[washguy]

Ripper just the wrong hand guard you have......and yep your barrel was moving from the heat prolly

you were there and it was Hot...so you answered your question.....there are some better choices for hand guards.....dont buy until the guys approve of the one you need...lol.......look at the apex for starters

:) Wash

[survivalshop]

Aluminum hand guards get hot just being in the sun. With out vents , makes it worse, then add rapid fire strings or prolonged firing , the heat adds up . 

[ripper51]

High 70's, low 80's here with no humidity is not all that warm. Normally have a 5-15 mph wind . Range has high berms that cause a swirl but also an "Easy Bake Oven effect".  @Washguy- yepper, some of the stringing was me trying to avoid deep frying my support hand. While the handguard is completely open towards the muzzle end and has these wonderful little round holes at the barrel nut end, in between gets a mite warm. Looked at Apex, one of the "dealers" here in town had one. DPMS Free Float Tube Handguard LR-308 Rifle Length Vented Aluminum Matte caught my eye as it appears to be the vented version of what I have. If it reduces the heat slightly, my oven mitt stands a chance of not bursting into flame. Tried a normal shooting glove- unfortunately the rubber melted pretty quickly. Don't think Creedmore would take it back under warranty. The original handgurads of course were not free floated but were ventilated enough that the heat didn't seem to be an issue. Didn't like the torsion however from the sling imparted to the barrel.

Originally thought I would configure this like the M110 or an oversize AR. @survivalshop, Just gives me impetus to have a good sight picture during rapids and a CO2 extinguisher for afterwards.

[washguy]

Ripper The DPMS slotted tube handguard isnt gonna help much.....time to bite the 308 bullet and get an APEX free float......if you can chew gum and walk at the same time you can make the change yourself

get a 308 claw and a barrel wrench....maybe a low pro gas block/gas tube too

ive got this on a 6.8 now they have em for 308's

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=1118

or trx battlerails :) Wash

https://troyind.com/rail-systems-accessories/rails/308

Edited April 25, 2014 by washguy

[N Jensen]

I have been shooting LR 308 and 6mm match rifles for some 5 years now. Yes the steel hand guards heat up.

 

I have a white oaks float tube with vent holes alone the top. However, the gun gets super hot. When I lived in Vegas during the summer, even the AR 15 match rifles would get super hot. We would place wet towels over the float tube after 300 yds was over and then kept the rifle in the shade until 600yds. But after 10 rounds and with the sun beaten down, the float tube would be hot enough to give my thumb 2nd degree burns If I didn't watch it. I just deal with it, the gun gets hot and I wear glove or use a towel to pick it up after 22 rounds.

 

When the gun gets that hot I found I have to drop the loads down as well during the hot summer months. Having a semi auto match rifle in 308 and a new 260 cal upper on the way. They are fun to shoot, good accuracy as well.

 

I sent you a personal message as well.

Edited April 25, 2014 by N Jensen

[ripper51]

This rifle is a hoot to shoot. When I do my part it cloverleafs 10 rounds at the x ring at 300 in rapid prone. Shot the center out sitting rapid at 200 and only dropped 2 points at 200 standing. During the cold months here, the freefloat tube was so hot I think we used it for group warmth but it cooled off quickly. I adjust loads for my M1A and for this LR308 depending upon the expected temps. However, I learned that VV N150 and N550 are relatively temperature insensitive. IMR 4895 seems to be fine but my tack drivers always are with varget. But Varget is sensitive to heat.

Got both the DPMS vented handguard and the TRX. APEX looked nice but I'll try these two first. There used to be an outfit called coolguards that made these but can't find them anymore.

And yes Neil, stringing at 600 was a  problem until I started over with my prone position setup. If I can shoot 768 with an M1A I should be able to better that with an AR platform, yes?

[N Jensen]

I see no reason you couldn't match your score of your M1A, maybe even shoot a little better.

[ripper51]

Had TRX and Apex in hand, put them on, took them off. Sent them back. I guess I am kind of a minimalist. Nice rails but too many places to hang things I really won't need. Put them DPMS slotted free float tube on. Had two of them, so I used the aluminum paint that supposed reflects heat on the inside of one. Yup, it reflects heat alright. Needed to attach a refrigeration unit- guess that's why those TRX and Apex had all those slots? :))

Put the other one on. Spun it down tight with a strap wrench. Slots and stars aligned just right. Put the Sling stud in the slot at the bottom, all the way forward. Am using the KNS Precision bipod and sling swivel stud. Seems to be fitted just right. It was 89 today with little breeze. Went out, did 200yd rapid sitting, 20 rds in 4 mags. Cleaned the target. Moved back to 300. 4 mags of 5 apiece rapid prone. Cleaned the target. Rifle was hot. Handguard was hot, but not unreasonably. Still had to use an oven mitt instead of a normal shooting glove but This seemed almost OK. Then I saw a gent with a Match A2 AR15 cussing at his rifle with the free float tube because it had melted his shooting glove and burned his hand. Hmmmmm

[Rsquared]

An AR-15 compared to a 308? Not a fair comparison.

 

Now with that said. I don't know what you guys are doing. My AR-10's may get hot.......but that's only after shooting hundreds of rounds. I mean.......HUNDREDS of rounds.

 

AR-15's? I've shot the hell outta my SBR's. Yes...they get hot. But not too hot to handle (once again.....hundreds of rounds).

[washguy]

An AR-15 compared to a 308? Not a fair comparison.

 

Now with that said. I don't know what you guys are doing. My AR-10's may get hot.......but that's only after shooting hundreds of rounds. I mean.......HUNDREDS of rounds.

 

AR-15's? I've shot the hell outta my SBR's. Yes...they get hot. But not too hot to handle (once again.....hundreds of rounds).

Same here :) Wash

[ripper51]

I have been shooting factory M80, 147 gr. I moved up to FGMM 168gr factory. For 600yds I used 175gr FGMM. None of these were hot loads or reloads. Glad you Rsquared and washguy haven't had that experience. I also have an AR15 A2, Colts. It has never heated up much unless the outside temp was over 90 and I have burned thru a hundred rounds or so. AR15's do heat up. LR308 Classics with stock handguards do heat up rapidly. LR308 Classics with an enclosed free float tube (no vent slots) do heat up rapidly. AR10's? Couldn't say. Can't remember off the top of my head who the maker is, but someone makes free float LR308 tubes that resemble AR15 handguards with heat shields as well as vent. These didn't have all the slots and rails that the APEX or TRX have. Just reporting what I have found so far.

[survivalshop]

Was it JP's that had a heat sink under the hand guard ?

Edited May 4, 2014 by survivalshop

[ripper51]

Group named Coolguards used to make some free float tubes that were ......cool. Can't find them anymore. Website is for sale.

[ripper51]

@survivalshop. Not sure who JP is. Have seen aluminum inserts under handguards for years. Do not have this problem with M1A and it has a solid fiberglas handguard.

[survivalshop]

 

Thermal Dissipator™

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[ripper51]

Know anyone who uses them>?

[survivalshop]

Nope .

[ripper51]

Saw a lot of 3 gun shooters on the website. Looks like the heat sink is built for their barrels and weapons. Good idea though.

Thanks

[392heminut]

Know anyone who uses them>?

About the only ones I've seen using them are 3 gunners, and not very many of them.

[ripper51]

Thanks to all for the comments. I am "spoiled" I guess by the M1A. AR15 & M16's I have had had a tendency to run a tad hot but you sort of expect that in certain situations. Ar15 that was set up as a Service Rifle for High Power and CMP matches never ran hot. I am shooting a larger round in a larger barrel and expected some heat but not like I was getting. So far this vented DPMS seems to satisfy me. Probably as close as I will get to using an AR10/DPMS LR308 in a match will be local matches. Think I also need to re-think the rear sights and call in an expert (or send it to one). While at first I thought of tricking this out to closely resemble the M110, it probably would cost me the equivalent of an M1A Supermatch. Probably will keep this one as it and use it to annoy anti-black rifle liberals.

[gnatshooter]

Think I also need to re-think the rear sights and call in an expert (or send it to one).

 

While considering rear sights -- if you like a notched rear leaf -- consider this item. It's the only dedicated notched rear leaf sight that's adjustable for elevation and windage that I've been able to find anywhere. Guldang pricey though. And I had to find a machinist to make me a replacement rear leaf with a smaller notch. The original was ridiculously huge, at something like 0.12" and my custom notch is 0.06". Should have gone 0.055". Hm. So maybe I'm not recommending it all that much. But still. There's lots of rear sight options out there if you like peepers. If you don't like aperture sights, your options are limited.

 

Edit: Think of how many pistols out there come with peep/aperture sights, and wonder why there aren't any. It's for a good reason.

Edited May 8, 2014 by gnatshooter

[Matt.Cross]

 While at first I thought of tricking this out to closely resemble the M110, it probably would cost me the equivalent of an M1A Supermatch. Probably will keep this one as it and use it to annoy anti-black rifle liberals.

 

I have done exactly that, and it was very rewarding. Roughly 3K later, it still dominates the range, and everyone who knows ARs moseys to my firing position to drool on it while the range is cold.