Realistic 10-shot groups

[Hondo64d]

To expand on my comment about sample size in load development, below is a series of charges from my latest .308. It is an Aero Precision Solus with a Bartlein 3b barrel. These are all 10 shot groups. Any one of them will be more than adequate for shooting critters out to as far as that bullet/velocity combo will maintain good expansion velocity. No one charge shows any statistically significant improvement over the other. To determine which one is different, I would need to go to more shots per group.

Much of this has to do with our goals. I tend to waiver back and forth between "good enough" and "the best it can be," so I have for the most part settled on 10-shot groups as my best compromise.

John

 

[Hondo64d]

You only need to worry about your first shot on a cold barrel. If your first shot goes in the same place everytime with a cold barrel, you're good. If you want to burn ammo for ten shot groups. Hell yeah I'm all about burning ammo. That's the fun of having a firearm. Real world your first shot is the most important shot for hunting

If you want to know where that cold bore shot is going, then repeat your cold bore shot 10 or more times at the same POA. Otherwise you're just guessing.

John

 

[VinceMule]

45.2g is much better! Great shooting!

200 and 300 yard groups sort things out in a hurry, lean hard on the 200 yard groups.

 

[MtPockets]

But these are lightweight, high-recoil hunting rifles.

To me, this says it all.

The only shot worth worrying about is the first one.

Concentrate on cold bore one shot "groups" and call it a day.

1/2 minute 5 shot groups are outstanding for a hunting rifle. I see no need to waste components or barrel life chasing it any further.

 

[skipglo]

Realistic to achieve groups with X number of rounds depends on many factors but for most of us the number 1 seems to be barrel heating.

Don't trust anything said on internet forums.

A few years ago I did some tests. Cold to Hot barrel mapping. Using a Fluke to measure barrel temperature and spacing the shots as well as I could on time/temperature.

I did this with a couple 22LR and 2 centerfire rifles, 223 thin barrel and 300 WSM Heavy Palma each had a "pattern" that followed with barrel heating.

Maybe I'll find the notebook, maybe I won't. It's in a box somewhere. I can remember a few things. The PWS T3 Toggle 22LR was always 11 o'clock 1/4 MOA on first shot with Lapua Polar Biathalon and 3 o'clock 1/2 MOA on Blazer.

Different load, same rifle had a different "map".

Basic and nothin special, I'm just trying to put words to it:
1st shot "cold bore" was always in a predictable POI vs POA. Normal for all of us.
2nd to X, basically on POI vs POA and in the "window" for consistency. Where X is the number of shots at the pace normal for the task at hand. Hunting, PRS, Bench Rest, "lollipop" games, what ever.
X to how ever many, is where POI starts to disburse from POA and where it goes for a given temperature range. Say at 1 shot per minute you know that 2-5 are in the "window" but at 6 on the POI moves 1/4 MOA 9 o'clock, you can adjust POA 1/4 toward 3 o'clock until shot 9 then it moves down to 4 o'clock. (nor a real map).

So

If you want to make large round count groups, you would do well to understand what temperature your rifle likes. Pace your shots so that the rifle is always around that temperature. Understand your POI shift. The Heavy Varmint, Sendoro, Bull barrels have more mass to smooth out the heat window.

Probably clear as mud.

Yup!

 

[Pdyson]

The only reason to shoot 10-shot groups is because it's demanded by the actively PRS, NRL, prairie dogs, feral hog eradication. For competition I like to load develop with 5 groups, but if the first 2 rounds are way apart I stop and go onto the next powder charge, seating depth, or tuner setting. Once I find the sweet spot I shoot confirmation groups using the round count and time limit required by the competition. For deer hunting I expect to fire one round and no more than 3. Hogs can be one to 15 rounds from my AR. Light weight barrels are not made for for high rates of sub MOA fire.

 

[skipglo]

I think OP you answered your own question with your 2nd point. Heavy recoiling light rifles...it's you. Fatigue sets in fast and anticipation of that recoil... we're only human ! IMHO....be happy with 5 shots. It's a bit like weight lifting....Lift the maximum weight you can and perform the max reps you can.....then set it down and finish your desired reps with something Lighter!

 

[fseaman.js]

If you want to know where that cold bore shot is going, then repeat your cold bore shot 10 or more times at the same POA. Otherwise you're just guessing.

John

This.

If the intended use is hunting then knowing your cold shot is IMHO the most important.

For every endeavor, I was taught and follow, practice as you intend to use. This translates to rifle hunting as knowing your cold bore and probably having your "zero" to cold bore.

It does track with my first reply of knowing your "map".

I caused my own error on a elk hunt by not following this so became a little more strict.

The intended use was an elk hunt. Rifle was a Weatherby Mark V, rechambered in 338/26 Nosler from 338 Win Mag.

I had zeroed and practiced with a bipod on my rifle.

I removed the bipod for the hunt. Bad idea! First day of the hunt every shot was high.

Second day with the bipod back on. No problem.

In this case it was more of hunt like you practice.

 

[MarkInPA]

Increased practice never hurt anyone. Not sure why there is so much push-back to shooting more.

Agreed. No doubt that we spend more on time and resources but, I thought that this was what we liked to do, "shoot and reload". A day at the range is a day of fun.

 

[tony d willIiams]

I've been doing 5-shot groups for load development. Once I get a 1/2 MOA 5-shot group, I call it good. However, I'm finding that the same load opens up to 1 moa when I do 10-shot groups. I allow several minutes between shots to cool down.

Wondering:

1. Do others experience the same sort of thing?

2. I'm shooting with custom barrels (proof and fierce). But these are lightweight, high-recoil hunting rifles. Should I be demanding a 1/2MOA 10-shot group, or am I chasing a rainbow trying to make that happen?

I see guys at my range shooting 20-shot 1/2 MOA groups, but they are shooting huge bull barrel .223's literally ratcheted down to an enormous rest. I can see how that would be pretty consistent . What's a realistic expectation for the rest of us?

I find that in the desert the heat makes a massive difference. I am going to bring one of my Flukes with me, just to gather barrel temperature.
First, I used to not worry about ammo temperature. I would shoot 3~5 rounds, sometimes ten rounds, walk to the target, and back. Us old guys with shot lungs need exercise. I had my ammo on the table, or on a skin if I was prone shooting. Around 13:00 I fired a round. My rifle jumped up, smoke coming from places I did not even know there were passages. I do not remember where the round hit. The brass had expanded and would not exit the chamber. I purchased a brass rod as a knock out device. Thankfully no damage to rifle. I now keep my ammo against my skin, or in shade.
After five rounds have been fired, the groups are getting larger, sometimes +/- 1.5 inch. If I put the rifle in shade, bolt open, five minutes plus after each five rounds I can shoot +/- 3/8 inch all day.
Going north to another desert 200 miles west and 150 miles north, the zero point shifts 4 inches x 8 inches. Still a good zero point, just needs to be compensated for. When shooting at original place, still holding the original point of impact.
.338 LM 300 Bergers bullets, Norma brass. 0.003 clearance to rifling in chamber.

 

[tony d willIiams]

Agreed. No doubt that we spend more on time and resources but, I thought that this was what we liked to do, "shoot and reload". A day at the range is a day of fun.

Plinking is a blast. I use my 22LR and WMR for plinking. Helps to keep me in proper form, control of breathing and heart rate.
I also plink at different ranges and angles with my pistols.
Too much fun, and not expensive.
Especially if there are sage eating rabbits in the neighborhood.

 

[NotLongRange]

Well…if I was match shooting, that would be more of a topic of concern. I've never taken anywhere close to 10 shots while hunting any big game animal, so I

 

[NotLongRange]

More of an issue when match shooting vs. hunting. Completely different rifle setup and construction.

 

[Velvet]

I believe in consistency more than group size. To know how the rifle/shooter solution performs, you have to take a target and shoot a coldbore shot throughout the year, going through all possible environmental conditions. The final group with 20 or more shots is going to be the harsh reality of what you and your rifle have to give. A sub sub Moa group this Saturday is of no use to me if I can't repeat it every Saturday. I'd rather know that the POI doesn't vary than have a beautiful, unrepeatable group. When we have the animal in front of us, that coldbore shot is what counts, not the photo of the sub sub moa group. If you achieve consistency and sub sub moa groups every time, you're getting closer to the definition of orgasm.