Comparison of 3 box ammo choices at 545 yards, analysis?

[Joe L]

I don't reload any .308 so I am using Southwest Ammunition (SWA) 168 SMK, Fed GMMK 168 SMK, and Rem Prem Match 168 SMK box ammo. My Savage 10 FCP-K has shot all three well in the past and I have shot a lot of the Southwest Ammunition loads with excellent results at this distance. Today I decided to shoot 5 rounds of each at the same target, same conditions, using the SWA dial in DOPE at 545 yds, calm conditions, perfect for this comparison test. Here is the overall target result, starting with the SWA on the left, Fed in the middle, and Remington on the right. All shot in about 20 minutes, very calm wind conditions, fortunately for me.



Here is a close up of the SWA target



I have shot sub 4" groups with this ammo but did not do so today.

The Fed GMMK target



and the Remington



This is a heavy 24" barrel rifle, so my first thought is that the velocities are different for the three choices. If that is correct, then the SWA is the fastest, the Federal just slightly slower, and the Remington is the slowest. I don't have a chronometer to check the muzzle velocities. But the group size appears to tighten up slightly as the velocity decreases as well. I was pleasantly surprised at the sub 2" 4 shot group with the Remington. Even with the one round just barely off the paper, that Remington group was the smallest. This is consistent with what I have seen before but I haven't shot much of the Remington lately due to availability, plus the Southwest Ammunition cartridges have been doing very well for me in this rifle. Today's group is slightly larger than average for this ammo.

What is interesting to me is that the Remington group is tiny for 4 rounds out of the 5and it had the smallest group even including the one round off the paper.

So, am I correct in thinking that this comparison is similar to what one would see if reloading and changing the powder charge slightly? If these were handloads, would I just home in on the load similar to the Remington and then vary overall length to fine tune?

I know there is a lot more to cartridge manufacture than powder charge, and I haven't measured any other differences between these three cartridges. To me, the SWA and Federal are pretty close, with the Remington being a little better combination for this particular rifle.

I welcome any input or analysis. I realize this is a very small sample, but, for a newbie like me, I thought the results were interesting. I haven't taken the time to shoot comparison groups at this distance before. All three shoot very well at 100 yds, with a slight change in zero. I couldn't hardly tell the difference at 100 yds.

Joe

Joe

[eddiesindian]

fantastic info Joe......damm good shooting as well. looks like Rem won the day a?

[sharpshooter]

Just because the Remington ammo shot lower, does not mean that it is slower. A difference in velocity and pressure curve will change harmonics. You have to realize also that the rifle is recoiling before the bullet leaves the barrel, and a faster bullet will leave sooner before the barrel lifts to it's peak.

[Joe L]

Sharpshooter--thanks, good point, that is exactly the kind of explanation/help I was hoping to read. Looks like I need to borrow a chrono...and just start reloading specifically for this rifle.

I guess I was thinking that IF the ammo groups the same at 100 yards, then any variation at 545 would most likely be due to differences in the velocities. I need to run this same comparison at 100 yd AND chrono all three.

Thanks again,
Joe

[eddiesindian]

yep, chrono is an extremely useful tool.
my train of thought is tight at 100 = tight out to distance (wind dependant)
IMO, I believe that infact the Rem ammo is running slower speeds. Id bet that there running about 2600ish.
What elevation are you at?

[Joe L]

This was at 5800 ft, I think. Thin air. About 2730 fps for the SWA, not sure about the Fed and Rem. At least the 2730 matches my ballistics calculator at 300 and 545 yard dials.

Joe

[eddiesindian]

wow....Im in southwest tx...in town is about 3800, but out in the mountains where we shoot at were at 4200-4400.
well, either way...give it a go and let us know what you find out a?

[CharlieNC]

Repeat your evaluation again, and if you get the same comparison then you will have a good basis for conclusions. Assuming these were shot in the order listed, you could just say the groups got better as you shot more. Try shooting one bullet per brand, and repeat this until you get the five per brand; that will "even out" conditions, shooter, etc across the brands. One thing I learned after 45 years of technical work is you rarely trust a sample size of 1.

[Joe L]

CharlieNC--Thanks, I think you are right about the sample size. Biggest variable is operator, especially a green one like me. This morning I went out again and didn't get the parallax right and I couldn't group anything. Now I'm 260 miles from the 545 yard range. I will try at 300 at the local range. I also have some work to do on the cheek weld height and scope position. My neck is sore from 5 days straight of uphill prone. I make a change last night and went too far on the scope position.

Thanks for the suggestion.

Joe

[rotts4u]

I get about 2840 fps out of my 10 FCPl-k with the Federal 168 Gold match ammo at 700 feet altitude. I have not shot the others but the FED gives me these 3 shot groups at 100 yards. .4845", .5905", .4590", My savage loves them. So much so I am struggling to beat it consistently with hand loads.

[eddiesindian]

wow---260 miles from 500yd range?...........boy oh boy do i feel lucky living in the great southwestern part of texas...theres so many places to shoot for distance here...including a military base,d shooting range

[Joe L]

Eddiesindian,
Its cool in the mountains of New Mexico! Home base is in Midland, but we spend some time in Ruidoso, New Mexico. We have lots of national forest land there also. I will try 800 yards next trip, then it is probably reload/rebarrel time for anything past that.

[Joe L]

Just because the Remington ammo shot lower, does not mean that it is slower. A difference in velocity and pressure curve will change harmonics. You have to realize also that the rifle is recoiling before the bullet leaves the barrel, and a faster bullet will leave sooner before the barrel lifts to it's peak.

Sharpshooter--You're right, I think it is a combination of harmonics as well as velocity. The Remington hit 1" higher at 100 yards than the Southwest Ammunition load, but both grouped well. Perhaps the velocity spread is a little more than indicated by the shift in impact above with fixed dial in?

Joe

[eddiesindian]

Eddiesindian,
Its cool in the mountains of New Mexico! Home base is in Midland, but we spend some time in Ruidoso, New Mexico. We have lots of national forest land there also. I will try 800 yards next trip, then it is probably reload/rebarrel time for anything past that.

Theres mountains east of El Paso Tx. where you can shoot from 10ft in frt of you out to a mile. The norm for us on any given sunday is we,ll set up steel swingers from 1/2/3/4/5/6/7/8/9/ and my hit alarm (as i call it) at 1000. we set up flags all over the place for wind direction.
I can almost garantee that you can hit out to 1k with whatcha got right now, just gotta calculate the drop on those rem rds

[Joe L]

eddiesindian--that sounds like fun! I will find a place to do that a little closer to home base.

I also want to make it clear that the Southwest Ammunition rounds are excellent and the price is right and the availability is good. I am very happy using their ammo all the time. For this particular test I did not group those 5 rounds as well as I do normally and, if that made the ammo look "inferior" to the much more expensive store ammo, I am sorry. There is definitely some shooter variation in the 15 rounds shown, and maybe even some luck with the Remington. Until I have duplicated these results a few times, this was just a pleasant educational experience wherein I shot 15 rounds well on one day and it appears the velocities are different.

Joe

[eddiesindian]

roger that joe.

when I "feel" like getting down to the natts ass as far as load development and patterns, Ill bolt my Savage up to a vise Ive made and removed human elemant/movement...a little time consuming but heck waht else are we to do....stay home and twittle our thumbs?

It is indeed fun when all my close friends and shooting partners show up out there in the valley where we have the 1K set and everybody participates in setting up the swingers/flags etc....
Ballistic drop and data that youve come up with is really put to the test. Ive smakcked every plate out to 1K with one shot a piece before with my savage...that was a great day..ther was some luck on calling the wind that day. by the time i got out to 1K i was holding 4moa for x-wind.
I even have a HD Camcoder and will at times not shoot but film my shooting partners while there executing there shots. The camcoder has a powerful zoom on it and I can zoom in and the shooters finger on the trigger and actually see the finger prints on his finger! lololo...Its full 1080 HD. I will also film us shooting the gamot from 100 out to 1K. If anything, it makes for some great fun even after the shot and my buddies will come over to the house and we watch the shooting event full 1080hd and let the shooting stories begin!
LIke I said before Joe. I really think you just need to figure your speeds and calculate the drop and you can smack out to 1K. The one thing Ive found out with ballistic drop calculators is that the more correct "ALL" the inputs are....the more of a gaurantee you,ll have of being spot on from 100-1000.

[Joe L]

Just got home from another trip to New Mexico...and the 545 yard range. Today I could not duplicate the results from two weeks ago, although I didn't try exactly the same test. First was 5 rounds of Fed GMM 168 at 100 yards to confirm zero, all OK. Then I went on out to 545 yards, with two groups using the Southwest Ammunition 168 using the dial in from 2 weeks ago, then 5 rounds of the Rem Premier Match, then 5 more rounds of the Southwest. Total 5 rounds at 100, followed by 20 rounds at 545.

The Remington rounds today shot well at the same dial in as the Southwest, which was surprising compared to two weeks ago when the Remington needed 0.2 mils up more dial at 545. The good thing is that I only had 2 rounds where I knew I had faltered on technique, out of 25 rounds. One was no follow through, and the other was when I stopped seeing the target just before releasing the shot. Other than those two obvious errors, I had 23 "good" hits. Also, I was comfortable today behind the gun after making a cheek pad and scope height/relief adjustment. I was still seeing well on the last 5 round group, unlike previous visits to this range where I was having problems after 15 rounds.

I think the sample size I used for the original post from 2 weeks ago was just too small, as is today's, come to think of it. Today, the rounds I shot seemed to behave the "same", instead of with groups off set enough for one to conclude the velocities must be different. I think two weeks ago was a fluke. Today was good. Much more comfortable behind the gun, allowing me to shoot well for more than 15 rounds for the first time. This was a good result for me.

Now, just more work on technique and consistency. The biggest variable is me, not the ammo or the rifle or the scope, me.

Joe

[CharlieNC]

[QUOTE=
Now, just more work on technique and consistency. The biggest variable is me, not the ammo or the rifle or the scope, me.

Joe[/QUOTE]

Wow; sounds like me! We tend to spend too much time refining the gear instead of good practice time at the range.