.308 which round shot better?

[TXAZ]

Following the last post where I shot 3 shot groups in calm weather, I tested 8 different models of .308 rounds, each in a group of 10 shot on a windy day.

The best 2 (so far) are Federal Gold Match Sierra BTHP 168 and 175 gr rounds seen in the attached pictures.

These were shot off a bipod in a 17 mph / gusting to 24 wind shifting from 12 oclock to 3 oclock. (Yea I know I should have waited for a calmer day)
Here are the target pictures of these 2 different rounds. Both were shot from cold bore, with that hit identified.

I'll go back and try this again (adding Berger 185's) in calmer weather.
Question to you gentlemen is, which round is shooting better? If you exclude the cold bore shot, both MOA's are about 1.4".
That and any other feedback appreciated.
Is there an accepted way to measure the X and Y axis differential to get a better sizing of the group?

 

[BourbonCowboy]

I can't answer any of the questions in your post, but I do appreciate the info that you shared. I've recently inherited an old Winchester Model 100 and plan to do a little hunting with it. This is the kind of information that will help me choose my ammo...if I can find any.

 

[Bfglowkey]

How fast did you snap them off? My opinion is the 168s....vertical stringing ( and not by much...its all one hole) could be heat related.
The 175s do look pretty damn nice and less fliers. Seems like you have a serious problem lol

 

[44 AMP]

Question to you gentlemen is, which round is shooting better? If you exclude the cold bore shot, both MOA's are about 1.4".

I'd say neither. Since both group sizes are the same, then neither is showing any marked improvement over the other.

What range and from what rifle are nice things to know, as well...

Group size is normally measured center to center from the holes that are furthest apart. X and Y axis spread requires a statistically large enough sample for any meaningful information and a few groups isn't enough for anything other than a general trend, AND of course data from one rifle is meaningless when shooting any other rifle.

 

[TXAZ]

Thanks 44AMP and all.
These were shot at 100 yards, wind 17-24 mph from 12-3 o’clock, Daniel Defense Hunter 18” barrel semi auto.
Cold bore shot on each group is circled.
Additionally Hornady 150 SST’s and Winchester 180 power points both looked more like a goose gun shotgun pattern.
I’ve order 5 more different rounds 2 x cheap Wolf ammo types, and 3 more different match rounds and hope to have a fair characterization of each for my rifle.

 

[langenc]

Just shot it. You wont get much beter. What are your goals for the rifle/ammo.shooter.

Some pf us posting here will never get that kind of groups.

I dont kpow anything about the rifle but if you want better groups Id get a lighter trigger, most likely.

 

[jrothWA]

Evening BourbonCowboy,

Is the SN of your M100 a numeric SN or starts with a "Alphabet character then number?
Just #'s then made before 1964, with the Alpha character, is after.
Either way, call following number: 800-852-5734, this is the Winchester / Olin Firearms Notice, for confirming is the M100 FP was replaced by an existing recall, if not listed they send a new FP.

Also send a PM , I have a take-doen procedure to it.

 

[bfoosh006]

I would say from that days groups... the 175gr FGMM is the better group.

If you can find any, I'd try some Hornady 155gr Amer. Gunner as well.

IMHO, those are outstanding groups from a Factory S/A 308... especially if it is a new rifle.

I would suggest you clean the barrels bore... just to try and "eek" out any extra accuracy.

I use the VFG Felt pellets ( and adaptor ) , Kroil and JB Bore Bright ( All available from Brownells )

Watch some of the videos.. https://www.google.com/search?client=firefox-b-1-d&q=JB+Bore+polish

Some of my best 10rd groups were fired after cleaning with the above mentioned "system"

 

[T. O'Heir]

"...waited for a calmer day..." No point putting off your fun.
Off a bipod really isn't a solid enough rest for load testing. Got a couple sand bags?
Consistency is more important than group size. Mind you, the fact that the cold barrel POI isn't the same matters for hunting. Not so much for target shooting.
You'll find the 175's do better at distances past 600. The 168's out to 600.
How'd you measure the wind? Just curious.
Measure from the center to center of the two widest holes.
"...looked more like a goose gun..." Hunting bullets vs match bullets will do that. Consistency with them is more important too.

 

[stinkeypete]

1. For hunting and if those are factory loads, that’s good shooting!
2. At 100 yards, consider the effects that wind, thermals (hot spots on the range with updrafts), the bipod and your marksmanship might contribute.
3. I commend your photo, it’s a good way to record your data. Myself, I always plunk a little pocket ruler near the groups so you can overlay two groups in photoshop and have them scale equally.
4. To compare groups using statistics in two dimensions is a bit more work. Without going crazy, recall Pythagoras- x2 + y2 = r2 and as you are making ragged holes, shooting each shot at a separate dot will help you measure. After much fussing, I’ve decided that simply holding the two groups up to the sun then centering them by eyeball tells me which is best.

For me, I would pick the 175’s because the group appears to be forming about a circle and the cold Bore shot is not a high flier, and it’s the lighter bullet so I assume the faster load- favoring longer flatter shots.

The 168s hint at vertical stringing. Thinking about the patterns I have seen from barrels, it brings to mind what the end of the barrel might be experiencing in oscillation as the bullet exits.

The good news: both look pretty good, either one works for me!

The bad news: I think you should shoot those two groups again on a different day to see if the results are repeatable. That’s the “re” in research! Redo it, see if the pattern holds.

I’ve thought quite a bit about how to do a statistical analysis of groups so we can compare the standard deviation. The result is that we need the x,y coordinate of each shot which is hard once you start making ragged holes. Coupled with the fact that expert competition shooters don’t seem to do this... they are looking at the radial distance from center... well...

Math and physics are powerful tools, but they describe reality... not define it. Shoot another data set!

 

[TXAZ]

Thanks stinkypete.
The rifle is a way better shot than the guy behind it.
I’ve also noticed how important the cant angle of the rifle as the Steiner scope sits up 3” from boresight, and put a level on the rail.

I shot 13 more trials today in the wind, the Federal 168 / 175 / 185 all look pretty good.
Then we threw in Berger 200 gr. Tighter group than federal but they had to be manually inserted as they are too long for the magazine.
(See my other thread on Wolf ammo, 5.6 MOA. )