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View Full Version : M4 ramps on AR15 and Hand Guard question?


Mattp27
February 7, 2011, 07:20 PM
Ok I have made a couple of post about my new barrel but I just want to get some feed back before I order. Here is a pic of my current barrel. from the reading Ive done im 99% sure my gun has the M4 feed ramps

Here it is.
http://partlowphotography.smugmug.com/Other/Forums/Barrel-Feed-ramp/1180579348_yJgrw-L.jpg

Next question. I have a Larue Tactical 11.0 hand guard. I am planning on getting the 20" WOA Varmint Barrel. It is a heavy barrel that comes with the gas block. Problem is I know I will not be able to install gas block and slip my hand guard over it. (The Larue low profile block barely fits) Does anyone think I will have enough room with a rifle length gas tube/block to install the handguard then install the block? I dont mind just the block sticking outside the handguard.

Here is a pic of my current Larue on my carbine barrel.

http://partlowphotography.smugmug.com/Other/Forums/Hand-Guard/1180578360_aRYFL-L.jpg

Thanks for the feedback!

Incognito
February 7, 2011, 09:16 PM
Yes, those are M4 feed ramps. If it were me, I'd just buy another upper (the way you want it), and leave that one the way it is.

Technosavant
February 7, 2011, 09:28 PM
Yup. M4 feed ramps.

As for the barrel/gas block, if I understand your question, you are saying that you don't think the gas block will fit underneath the handguard and you wonder if a gas block in the traditional rifle location will be out of the way and in front of the handguard.

Yes, an 11 inch handguard won't cover a gas block at the "rifle length" spot- that's about a 12 inch distance from the upper, so you should be fine.

thesheepdog
February 8, 2011, 10:05 AM
Yes you have M4 feed ramps.

A bull barrel will be very snug under most "Tactical" hnadguards. The reason is because "Tactical" and "Varmint" don't mix well. The military doesn't want to haul a heavy bull barrel around with them.
I know Daniel Defense rails will support up to a 1in O.D. barrel. But, you still have to add a GB. So, you may consider a lighter weight barrel, or a new handguard for the 20" Bull.

I would caution you on having your GB stick out past the HG, especially if you're going with a low-pro version. Low-pro's are nice, but they don't have the ruggedness of the FSP GB's (pinned on).
I haven't seen my low-pro's come loose, but, if you plan on giving your rifle some abuse, you may need to consider a new setup if your heart is set on a 20" Bull Barrel.

My suggestion: Don't go with a bull barrel on an AR. Medium weight SS barrels are plenty accurate (Sub-MOA past 400 yards in my experience).
You may look at fluted barrel in medium weight.

Mattp27
February 8, 2011, 12:46 PM
Ok what about going with the 18" WOA SPR barrel with the mid length gas tube. I want to be able to shoot out to 600 yards and maintain 1 moa.

thesheepdog
February 8, 2011, 02:22 PM
Ok what about going with the 18" WOA SPR barrel with the mid length gas tube. I want to be able to shoot out to 600 yards and maintain 1 moa.

The SPR barrels will suit what you're needing. I shoot sub-MOA with my 16" DD at 400 yards-it uses a Lothar Walther barrel.

I think the WOA SPR will work just fine with your current HG.

Have you ever shot at that distance before? Most quality AR's are highly capable of shooting MOA groups-even SBR's can do that. The only difference between shorter barrels and longer barrels is the elevation adjustments you will have to make at further distances (more velocity = faster time of flight = less dope = less adjustment on optics)

I've seen guys shoot 400+ yards with 11.5 SBR's.

RockyMtnTactical
February 8, 2011, 03:25 PM
For sure those are m4 feedramps.

Mattp27
February 8, 2011, 03:38 PM
My local range has a 600 yard my 16" carbine barrels shoots about 3 moa on a good day. I want to see a tighter group closer to 1 moa and have a bit faster velocities. The 18" should help a little with the velocity. Now that I have decided on that. WOA offers a mid length gas system or a rifle length. I know if I do the mid my gas block will be hidden if I do the rifle it will be exposed. I have a larue low profile gas block. Are there any advantages over the two? Will I see any improved accuracy with a rifle setup over the mid length? Also planning on installing a JP Enterprise Bennie Cooley muzzle brake.

thesheepdog
February 8, 2011, 03:45 PM
My local range has a 600 yard my 16" carbine barrels shoots about 3 moa on a good day

That sounds more like the shooter and not the gun, unless this came from a bench? I have never seen an AR that inaccurate. 2 MOA is the biggest group I have seen from a bench with cheap ammo. You may consider a different ammo as well.

Like I said, I can shoot Sub minute groups with mine at 400 yards, no bipod, sling or bench-prone position.


The Rifle length gas sytems will shoot the smoothest. Mid lengths are still a step better than carbine lengths.
I have a mid length Grendel upper and a carbine length upper in 5.56. Never really seen a difference in function between the two.

The JP Brake is awesome from what I hear. Almost eliminates recoil. But I wouldn't buy one just yet, until you can get an accuracy report on your new barrel.

Mattp27
February 8, 2011, 03:55 PM
On a bench all the time. Bipod on front and sandbag on rear. It may be the 55gr bullets to and wind change. It does ok out to 330 yards. I can hit an 8" steel plate 9 times out of 10. What I hate about it is the first shot is almost always 2" high and 2" left with a cold bore at 100 yards. Then shoots around 1 moa. It just isn't consistent. That's what I want. I know a cold bore shot will be off a bit. My Remington 700 .308 is consistently 1/2" high on the first shot at 100. I can deal with that. Not 2" and 2". I have a quality two stage trigger as well. (Gelissie) It seems to do well once it has heated up. But I missed a deer this year at 170 yards taking a neck shot luckily the deer ran and stopped at 150 yards. Second shot was dead on. Not so lucky for the deer.

Mattp27
February 8, 2011, 04:02 PM
Oh I am also shooting my own reloads

Bartholomew Roberts
February 8, 2011, 04:11 PM
You need to ditch 55gr bullets if you are shooting for accuracy at longer distances. There just aren't that many that are any good. If you wanted to stay in that weight range, I'd step down to 52gr match ammo.

As for the cold bore problem, can't help you there; but I agree that seems like an unreasonable shift in the first shot.

Mattp27
February 8, 2011, 07:16 PM
Well i ordered a WOA SPR with matching bolt and having it bead blasted. Hope I got a good setup.

Blackops_2
February 8, 2011, 09:15 PM
I think you'll have good results with the WOA. I've never used one, but i've yet to read a bad review either. I also agree with Bartholomew, i would ditch the 50gr class bullets and move to 68+. Preferably 75gr, the WOA you have is a 1:7 twist correct? As for gas tube i would also choose rifle. Just my preference. Rifle length gas tube = less recoil and more reliability, theoretically speaking. I like watching my bullets hit the target, or liked doing it when i shot often. I'm having a hard time doing it now, but i will regain the skill in a couple of weeks of getting behind the rifle consistently again. With an 18" barrel i just like the idea of a rifle length system. But a mid paired with a brake really doesn't move. A carbine on the other hand while not by any means a hard kicking gun it can still bite you if you don't watch it, lol while a friend and I were sighting in his RRA entry he got done shooting a group stood up and blood ran down his nose and stained his ACOG. :rolleyes:

Mattp27
February 8, 2011, 09:28 PM
Yes it is a 1-7 twist. Now what bullet will be accurate and be good for hunting deer? Most all the bullets I see are "match" bullets. So what are the best options?

Also what would be good to take out prarrie dogs?:D Because thats my main mission with this setup.

Blackops_2
February 8, 2011, 09:48 PM
I've never shot an animal with a match bullet. But i've shot snow geese with a 55gr FMJ. Sounds horrible but at the time they were destroying our 100 acre wheat field, so a friend and i lit up as many as we could. If placed right a FMJ will kill small game in instances. I don't recommend it though, which brings to this point. Some people have said that a match bullet is not ideal for hunting. Which in a sense is right, a match grain hollow point isn't designed to fragmentate. But i would imagine it would more than do the job, especially for a game like prairie dogs. See what the rifle likes i guess and then go at it.

Just to start off i've read good things about 69gr bullets and 75gr doing well in 1:7. Just read under the description of the sierra matchking 69gr that they're designed to be stabilized in a 1:7 twist and 1:10 twist. So yeah try an assortment and see what you like. I would go straight for the 69gr and 75gr. The way i am now, is i like the higher BC of the bullet the regardless the wait. I used to be all about speed. But seeing that plenty of people shoot to 1000yds with 168gr match Black Hills ammo @ 2650fps speed is not always vital. Same applies to 5.56 in most instances.

Mattp27
February 8, 2011, 10:08 PM
Well when I placed my order Paul at WOA said they had a 18" 1:8 twist but it was a rifle lenth tube. The 18" SPR with 1-7 and mid length the barrels are on backorder and it will be about 4-6 weeks. So I could change my mind. Would I be better off with the 1:8 and have a bit more versitality in my bulets sizes? I dont want to be stuck shooting only match bullets I like to hunt with this gun.

I could probably deal with the gas tube being exposed.

Blackops_2
February 8, 2011, 10:16 PM
1:8 has mixed reviews to me. Depends on the bullets you want to shoot. I've read that 1:8 is the best all around twist, and for your case it could be. You should be able to shoot anything from 55-69, so you still have some room for having better long range bullets and shooting heavier bullets. For me i plan on shooting 69-75 only and i had read some reviews of the 1:8 not stabilizing the 75gr. I had additionally planned to get a BCM SPR barrel for my build but i might shell out the extra cash for a douglas 1:7 SPR. I haven't decided yet.
Gas tubes are 13$ so you could get the 1:8 and use a mid gas tube.

thesheepdog
February 9, 2011, 08:21 AM
The 1:8's are fine for most grains. I have a 1:9 and have shot 75 OTM's just fine (at 100 yards). But a 1:7 would suit you better for what you're doing.

For hunting game, you want the best of the best. Barnes probably has some of the deadliest game ammo out there and all I hear is good reviews.

I have hunted with just plain o'le Silver Bear SP's and took my first deer with one shot @ 185 yards.

Bartholomew Roberts
February 9, 2011, 10:08 AM
I own both 1:7 and 1:8 barrels,. Unless you plan to single load rounds that are too long to fit in the magazine, 1:8 will do just fine.

1:9 is borderline for stabilizing the heavier 75gr and 77gr rounds; but I've never seen a 1:8 with that problem.

Blackops_2
February 9, 2011, 11:08 AM
So you shoot the 75s just fine bartholomew? Curious to the topic at hand because my decision on which SPR barrel i'm going to get will be based on twist. I will be shooting 69-75gr only. Thing is the douglas barrel thats 1:7 425$ while the BCM 369$.

thesheepdog
February 9, 2011, 11:35 AM
I've shot 75 OTM's out of my 1:9. They work fine at 100 yards. I haven't tested them past that.

Bartholomew Roberts
February 9, 2011, 01:04 PM
No trouble with either the 75gr Hornady OTMs or the 77gr Sierra in 1:8. However, I shoot factory ammo and nothing that can't fit into the magazine - and the longest I've shot the 75s is out to 500yds.

Blackops_2
February 9, 2011, 02:24 PM
I plan on buying bulk for my SPR to start. So i guess i'll stick with the 1:8 save a little money too.