16" vs 20" HB's

survivalshop · February 11, 2014

Target photo's , I had a few fliers on my part today & breaking in a new rifle with different loadings ,I was more interested in function than groups , although they show potential . I can play around with charge wt. of the IMR 4064 one I remember to take my Chronograph along for the shooting session.

All the Barnes Bullets were set to the COL in there Manual , so that can make a difference , my chamber may like a different one, have to do more testing . Even the SMK's with 4064 can use a little tweaking , but I;m confident once this rifle gets a few more rounds through it , I can put it against the 20" to see what happens . I was not to that conclusion a week ago .
The fact that I can use PMags is just great. I have to come up with a way or be more vigilant , of the PMags , especially the Gen. 3 , its longer than the Gen. 1 & I keep hitting the bench with it or resting it on the bench & not knowing it . I think its throwing some of my shots off .

Brass pile

I tested the G2S trigger pull , I had 2# first stage & 1 1/2 # second stage , not whats advertised , but I'll take it <thumbsup>

Edited February 11, 2014 by survivalshop

FaRKle! · February 11, 2014

Geissele said it pertained to DPMS lower's...

I wonder if they meant specifically DPMS brand lowers or DPMS pattern lowers. I haven't had any issues with my Giessele SD-E in my MK216 which uses a DPMS pattern lower. I don't think Bubbasks has had any issues with his Geissele High Speed National Match in his DPMS branded lower.

Edited February 11, 2014 by FaRKle!

unforgiven · February 11, 2014

Pretty good brother SS can't get use to that greenery when more than half of the country is covered in snow. :blink:

survivalshop · February 11, 2014

I was in one of the only dry spots around .

I wonder if they meant specifically DPMS brand lowers or DPMS pattern lowers. I haven't had any issues with my Giessele SD-E in my MK216 which uses a DPMS pattern lower. I don't think Bubbasks has had any issues with his Geissele High Speed National Match in his DPMS branded lower.

May be something with the G2S trigger , because I have the SSA in my other DPMS lower & no problems at all .

D.R.D. · February 12, 2014

When are the 16" and 20" going head to head again?

survivalshop · February 12, 2014

Well I had problems as you can see, with accuracy with the 16" rifle the way it was built & there would have been no competition between the two right off the bat @ 100 yrds. . I believe I have corrected the problem as has been described in the earlier posts , the fitment of the two unmatched Receivers was the root of the problem, I changed the BCG out because of the wear on the bolt & I had a new BCG siting around , so in it went also.

My goal is this spring/summer , not many long range , ranges down here , so getting to one, has to be set up . Should have 200 yards done shortly , after I get some more reload data on IMR 4064 with the rifles .

This rifle shot real well with just the MBUS on her @ 100 yards , but putting a scope on , magnified problems with its grouping potential , so I built a new rifle around the 16"HB..

I have a lot going on now that I'm retired & this is just one of them. <laughs>

98Z5V · February 13, 2014

SS, that is an awesome update, man! That's some good work, right there. <thumbsup>

survivalshop · February 13, 2014

Hell, 98 , I had to build a new rifle around the 16" HB just to get to use PMags ! <laughs>

I have to get some better photo's of the used Bolt lugs , the wear on it is something I have not seen before , looks like the barrel extension locking lugs seated into the Bolt locking lugs . Not rubbed , but indented , I have thought about this , I wish I would have head spaced it before swapping out the Receivers. I can HS it now , with the old BCG ,but I would of liked to see if anything changed since I did the bedding job on the Receivers.

I have also noticed that this 16" & for that matter , the 20" seem to shoot better groups with the old WC 846 ball powder than the IMR 4064 , but my development of 4064 is still too early to tell for sure . I believe the IMR 4064 will do much better at loner ranges than the WC 846 , but only further testing will see how that works out .

I also have to get some 175 gr. match bullets to set a load for them also.( I've never loaded for them before ) I have about a doz. Barnes Tac X 168 gr. bullets left & will do more testing on them.Not sure if I will ever purchase them again , I had problems loading them & with IMR 4064 , they were compressed loads , which I personally do not care for .

survivalshop · February 16, 2014

The Tango Down didn't match up to the DPMS 308 lower too good so,

on to the BRO AR 15 lower I have for my next build & while I was at it , the lower was so, naked , I put a new Milspec receiver extension ,Spikes Trigger system & mag release.

I loaded some test loads & will take the Chrono & both rifles tomorrow .

Edited February 16, 2014 by survivalshop

survivalshop · February 16, 2014

I've been doing some research on long range shooting & I was going to (& have been ) make the same load up for both rifles . I no longer believe I will be getting the most out of the platforms by doing that & will be making the best shooting load for each rifle , if that's the way it turns out

I already think the shorter barrel likes the WC846 better than the IMR 4064 . ( might have some thing to do with burn rate/barrel length ?) The 20" doesn't seem to mind ether Powder so far , I believe . My testing tomorrow will give me some better info .

Check this one bullet type, I have a few left , shoots very well from the 20". Its a stepped boat tail design, 170 gr.

left to right ,168 Hornady,168 SMK, 170 Stepped BT & 168 Barnes Tac X

98Z5V · February 17, 2014

I already think the shorter barrel likes the WC846 better than the IMR 4064 . ( might have some thing to do with burn rate/barrel length ?)

I think you're right on that - getting a complete burn before the projo exits the barrel. The WC846 is probably doing that, while the 4064 isn't. At least out of the 16". I think it's a good call - make the best round for each rifle, then pit the two different rifles against each other at distance. <thumbsup>

survivalshop · February 19, 2014

From what I have been reading , the Barnes bullets don't do well at longer ranges , so I may be leaving them out of any testing , for now ,that is . I still have to Chrono them though .They say its some thing about the groves on the bullet , disrupts air flow ?

Edited February 19, 2014 by survivalshop

survivalshop · February 20, 2014

Put some Chrono Data in the reloading section today from both rifles. Interesting results , I didn't do any Barnes Bullets .

survivalshop · April 6, 2014

Shot both rifles @ 200 yards today with the 175 gr. Nosler Match bullets with 39.5 gr. of IMR 4064 in the 20" & 40.0 gr. IMR 4064 in the 16" . Both rifles shot the same , both about the same groupings . I will take a photo of the target that I used for the fist shot stings after dialing both scopes in & also the last shot string , just to see if there was a difference between a some what cool barrel & a completely warm barrel after shooting in 85 deg. for a while .

Groups could have ben better & I blame me & not rife/ammo , I have shot better at 200 with 168 gr. SMK bullets .

I also shot my Heart Doctors CMMG 308 with an 18" barrel ( i think its 18" ) with my ammo & shot about the same as with my rifles. Good to see the tightening of his barrel nut , that was loose from the factory , is making MOA groupings & he was very happy .

I have to set up to go to another range to shoot over 200 yards & up . I've never been to this range before & will have to check it out first.

98Z5V · April 6, 2014

I like the results. You've put alot of time into this, and it's damn good data. <thumbsup>

unforgiven · April 6, 2014

You have put alot of time into this and have come out with alot of good info.Thanks brother. :hethan:

D.R.D. · April 6, 2014

Yes, great stuff! It will be investing to see how velocity plays into the mix with the different barrel lengths at longer ranges, if at all!

survivalshop · April 7, 2014

The groups here show me a couple of things , I shot much better than this with 168 SMK 's , out of the 20" bbl. before . This is the first time @ 200 yards with the 16" bbl.. It seems I may be doing some more load development, I think I want to get some more velocity & will make various loadings at higher velocities just to see how they do @ 200. These loads I used were the best in ES & SD , that may or may not be what is needed to get this bullet out further. I guess this is why we test this stuff .

I also wonder how the 168 match bullets would have matched up to these groups , I didn't have any with me , something that won't happen again. . I know one thing that made the last groups to open up a hair , is the sweat rolling into my eye's & my glass's fogging up , did not help . I also didn't dial the 16 " bbl. to center the groups, because I am not sure if this loading is the final set up . I want to play around some more at 200 yards.
I also picked up some IMR 4895 , which Nolser reloading data reads 39.5 gr.'s is the one they found most accurate .

Sisco · April 9, 2014

Good thread. Thanks for the information. Just for the heck of it I am going to set up a comparison between the AR10 A4 20 inch barrel I have and an AR10 T 16 inch target barrel I have on order. It is kinda apples to oranges, since they are not the same model, but I know the 20 " is extremely accurate. It is kind of a comparison between length and thickness and which affects accuracy more. Armalite says the AR10 A4 should shoot 1.5-2 MOA and the AR10T carbine 1 MOA. Wjth the nut behind the gun, we will see.

FaRKle! · April 9, 2014

It is kind of a comparison between length and thickness and which affects accuracy more.

It might be a bit of a stretch to draw any conclusions on length and thickness and which offers a larger contribution to accuracy considering one of your barrels is 416R stainless steel and the other is chrome-lined 4140 steel.

Rsquared · April 9, 2014

This sounds like a length vs girth type of thing.

Couldn't resist.

Sisco · April 10, 2014

It might be a bit of a stretch to draw any conclusions on length and thickness and which offers a larger contribution to accuracy considering one of your barrels is 416R stainless steel and the other is chrome-lined 4140 steel.

didnt say it would be scientific, more an excuse to shoot off a few rounds in both of them. As far as length and girth, it is best to have both. I'm just sayin.......

98Z5V · April 10, 2014

This sounds like a length vs girth type of thing.

Couldn't resist.

I knew it was gonna hit... :yup:

Sisco · April 10, 2014

That's one of those I knew I was in trouble the moment I said it.

survivalshop · May 14, 2014

Well it seems there are no 1K ranges around me , so finding what these rifles will do at that range is not going to happen, unless I come across something & that's got me thinking about my bullet selection . If I'm not shooting past 600yards( longest in my area , an hour or two away ) , why even work up any more loadings with a 175 gr. bullet . I'm going to continue with 168 gr. bullets if for any reason then I have already got load & target data for this bullet in both rifles & they have much better groupings @ 200 yards .

Granted , I have not settled on a good load for the 175's yet & will take some new loads with IMR 4895 , which the Nosler data of 39.5 gr charge reads are the most accurate , we will see . I will be doing some Chrono data this weekend .

Damn !