.308 ammo comparison: accuracy and reliability

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Snakum

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Another one of those things I wanted to know but couldn't find in one place, so I'm posting my results over many, many rounds of ammo sent down range thru my Marlin XS7. Listed accuracy was the average over many three-shot strings, and all strings were shot with at least a ten minute cool-down between each group. All strings were from a bipod and using a rucksack or sandbag in the rear. No bench rests were used. This is 'real-world' accuracy where the once-in-a-blue-moon groups were merely part of the average.

The results were surprising in some cases, re. Georgia Arms and Silver Bear. YMMV of course.

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Rifle: Marlin XS7, stiffened forearm and Devcon bedded recoil lug area
Caliber: 308
Barrel: stock, 22"
Sights: Redfield Revolution 4-12x40 duplex reticle
Support: Harris 13"-32" bipod

Federal 150gr PowerShok SP ... BC = .289, Avg Vel = 2675
Accuracy ... 1 MOA to 250 yards, 1.2 MOA from 250 to 600 yards
Notes ... No missfires, accuracy very consistent

Barnul Brown Bear 145gr FMJ ... BC = ?, Avg Vel = ?
Accuracy ... 1.1 MOA to 200 yards, 1.5 MOA from 250 to 500 yards, 2 MOA at 600 yards.
Notes ... No misfires, accuracy was so-so, didn't eject well.

Barnul Silver Bear 140gr SP... BC = .250, Avg Vel = 2710
Accuracy = .75 MOA to 300 yards, 1.2 MOA from 300 to 500 yards, 1.75 MOA from 500 to 600 yards.
Notes ... surprisingly accurate and consistent, no misfires.

Georgia Arms 168gr BTHP ... BC = .488, Avg Vel = 2600
Accuracy ... .75 MOA to 500 yards, 1 MOA at 600 yards.
Notes ... almost mirrored Federal GM Match, consistent accuracy, large POI change over other loads.

Federal BTHP Match ... BC = .488, Avg Vel = 2620
Accuracy ... .75 MOA to 500 yards, 1 MOA at 600 (corrected).
Notes ... best of breed (it is the gold standard, of course), very consistent accuracy, POI change over other loads.

PMC Bronze 147gr FMJBT ... BC = .369, Avg Vel = 2751
Accuracy ... 1.5 MOA to 200 yards, .8 MOA from 200 to 400 yards, 1.4 MOA from 400 to 600 yards.
Notes ... generally good accuracy and reliability but some lots of ammo are all over the place, not consistent, brass good for reloading. Accuracy in the "good lots" was odd, in that it was over MOA under 200 yards then went under MOA past that.
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Hope this info helps someone else down the road. Appreciate any comments or suggestions on the data. It'd be nice to have more experienced voices weighing in, for those who come after.
 
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So let me get this straight. You're shooting a Marlin XS7, 22" standard contour barrel (thats all they come in) in .308cal., off of a bi-pod (nothing solid) using Federal Match ammo, and you are posting .75 moa at 600yds. Wow- I guess that beats my .22 Cricket punching the paper at 300yds with a .93 moa, using Remingtons new Mohawk ammo 32gr. hollow point "shorts". Keep up the good work.;)
 
Ya that is really use full as I just bought the same rifle. Mostly because of your write up and upon seeing it my self. Although from the sounds of it my fit and finish was a little better than yours, I am very happy with it and can't wait to get out to do some long range shooting. A friend told me he would sell me 200 rounds of that silver bear for 50 bucks. I told him I wanted but know I think I really want it.
 
It only shot sub MOA at the longer ranges with the GA and the Federal Match stuff. There are guys on the Marlin forums who say they're getting half inch or better groups at 100 with the stock rifle (no work done), but mine never shot that well even with the work.

Note ... the Federal Match shot .75 MOA only to 500 yards, and averaged 6" at 600 yards, just as with the GA match ammo. My bad. And yes, it was 168gr. And if you saw the other posts, the best groups weren't shot by me, but by one of my shooting buds.
 
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Ya that is really use full as I just bought the same rifle. Mostly because of your write up and upon seeing it my self. Although from the sounds of it my fit and finish was a little better than yours, I am very happy with it and can't wait to get out to do some long range shooting. A friend told me he would sell me 200 rounds of that silver bear for 50 bucks. I told him I wanted but know I think I really want it.
Click to expand...

I bought mine because I saw all the posts on the Marlin forums where guys were shooting amazing groups. i was a bit dubious till a friend of mine (also posts here) bought one in .243 and shot under a half inch right from the store. He sighted a second one in for someone else and it did the same thing. I know the poster very well and I believe him 100%. Mine never shot that well, and only broke 1" with all the work done on it and with match ammo, but it was always pretty consistent as the ranges went up as long as I let the barrel cool back to a 'cold bore'.

Also a note ... shooting Silver Bear before the work on the stock and bedding I was shooting almost 2 MOA at longer ranges (I think I listed the original group sizes somewhere on here). It only tightened up once I did the work on it. Yours may shoot it better right out of the box, though.
 
I guess folks are calling BS on the group sizes for the match ammo. Here is the raw data on the Federal. If it doesn't add up I'll change the accuracy notes cuz I'm not here to impress anyone with my shooting (I only shot one row of the data anyway), only to provide info on the ammo because I've gotten three emails asking for more info. I read guys on tactical rifle forums listing 1/2 MOA to 800 or 1000 yards for off-the-shelf varmint rifles, so I'm not sure why double that at less range is so hard to believe. Believe it or don't believe it. No biggie.

100 200 300 400 500 600
0.625 1.25 2.975 3.25 4.125 6.25
0.875 1.95 3.125 4.5 5.75 NA <------ My strings, obviously :D
0.775 1.45 1.725 3.6 4.4 6.125
 
I just bought an XS7 in .308. I'm glad to see these numbers. I have only shot mine one time and I didn't have a very sturdy set up. I can't wait to get back out there and try some more.

Snakum, You mentioned the Brown Bears not ejecting well. Do you think they got sticky from the lacquer? I heard about people having that trouble with semi-autos. I always wondered how they would do with a bolt gun. I have some but haven't tried them yet.

Great thread!
 
Pretty frigging good shooting there folks. Would like to see some of those fellows shooting those groups go up against my wife with her 22 cal Taurus revolver with the 2" barrel. So far the best she has come up with is .250 sub moa @ 450 yards with a 25 mph wind blowing from left to right. Of course now she has only accomplished this ten times in a row three times. So don't expect too much now, you heah. This little ole gal shoots down in the grand ole state of Georgia.

We haven't yet figgured how to attatch a bi pod to the 2" barrel so she just ops to shoot off hand at the present time. :rolleyes: J
 
Some of the Brown Bear sticking is the lacquer, some of it is the rifle (they don't eject all that well anyway), and some of it is the gasses/powder blowing by the case when fired.

And for those who still don't believe a good sporter barrel will hold MOA to 500 yards in no wind conditions with Match ammo come on down to Sanford, NC next Sunday and watch. You have an open invitation. Three or four posters on SH can shoot sporter barreled .243s to MOA at 800+ (they're the guys who made me want to try it) and lots of folks shoot 1/2 MOA with heavy-barrel Savages at that distance. Don't understand why it's so hard to believe with everyone else raving about Marlin's new barrels.

Come on down and watch and I'll show you what it'll do.
 
Thanks for another great thread, Snakum. Once again answering questions I had that I couldn't find info for anywhere else.

Still haven't gotten to the range with mine, but I'm dyin to check her out and have been trying to decide what brands and grains to try first. So, even though a lot of the fun is in doing all the research yourself, it'll be nice to have a good starting point to find out where the ability of my rifle stands as-is so I'll know where to go from here.

And I've been eyeing that Silver Bear after discovering it for my SKS so it's great to hear a positive report for it in .308 out of the XS7 as well. I'll certainly be picking some up.

From hands on only, workmanship and molding look and feel great. Myt have to throw on a limbsaver for an extra inch of LOP to the 13.25 it comes with. Just have to get her to the range and post some results now.

Keep up the in-depth reports. There are plenty of us who really appreciate it. :)
 
LOL, those are "internet" groups, and may or may not have any resemblance with reality.
Click to expand...

Yeah, it's easy...watch this.

I'm getting 1/4MOA at 988y from a Century built AK using Wolf Military ammo, off the hood of me old pick-up truck! See, nothing to internet accuracy reports!

Don't believe 'everything' you read, see or hear on the net!
 
yeah, look around at long range match results posted. at the match i shot last weekend, out of i think 16 F-class shooters (scopes, rests, bags or bipods), the high score was 378-6x. Perspective: a score of 400 would be 1 MOA. The "-6x" means the best shooter put 6 out of 40 rounds into a 1/2 MOA circle.

edit: and there was no shortage of high dollar equipment on the line... couple USO SN-3s, AIs, etc
 
Georgia Arms 168gr BTHP ... BC = .488, Avg Vel = 2600
Accuracy ... .75 MOA to 500 yards, 1 MOA at 600 yards.
Notes ... almost mirrored Federal GM Match, consistent accuracy, large POI change over other loads.

Federal BTHP Match ... BC = .488, Avg Vel = 2620
Accuracy ... .75 MOA to 500 yards, 1 MOA at 600 (corrected).
Notes ... best of breed (it is the gold standard, of course), very consistent accuracy, POI change over other loads.
Click to expand...

Ok call me stupid here but I have to ask this question just for my own sanity. How can you have Point of impact changes and a tight group? That does not compute in my brain for some odd reason. My understanding of ballistics, although small it is still basic math, tells me that is a physical impossibility. If your POI changes then obviously your grouping will as well, am I correct? So what that is telling me is, unless you are getting all your POI changes in the same groups, then something is way off on those numbers you have posted. Not calling "BS" here, just trying to understand your math on this. Thanks
 
FFIL, not really. imagine a standard 308 load has 43 grains of powder and shoots into 1 MOA. now load a group with 30 grains of powder. it may also shoot into 1 MOA, but the bullets are going slower and may land quite a bit lower.

read up a bit on barrel harmonics theories for another explanation of why they could be different POI.

e.g. shooting with and without a silencer can change POI
 
Ok let me rephrase this so it will be easier to understand, He is posting POI changes in the SAME STRINGS not variant loading data. As posted, he is saying he is getting POI changes in the same loads. I see nowhere in the data that he "changed loads" in each string, so varying POI's means inconsistent data correct? Or am I reading it wrong. I see in each one he posted a certain load with the BC's and velocities and what they did at each range. So how, with that data, can you have varying POI and consistent grouping?

Used the same firearm as well so barrel harmonics should be consistent as well.

Unless he means the POI is variant from the prior load string fired which makes total sense to me and easier to swallow.
 
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