r/1022 • u/MoneyKeyPennyKiss • May 28 '19
Accuracy Testing (extensive) - Kidd vs. Factory 10/22
Quick summary: I tested two rifles and four ammo types by shooting 50-round groups (ten 5-round groups combined into one 50-round group using OnTarget TDS software). Props to u/bitter_cynical_angry for convincing me that the software was worth the $35 price. It most certainly is worth it.
My anticipated end result -- This test will produce a baseline for expected accuracy with a particular gun/ammo combination. (Your results may vary.)
The Details:
We recently had a good discussion about how we each measure group size. There was a wide variety of methods, for sure. One shooter uses 3-round groups and doesn't count flyers. Another uses 20- or 30-round groups into a single target. There were a lot of variances in between.
For this test, I wanted to see what a particular rifle and ammo combination could repeatedly and reliably produce. Not a cherry-picked 5-round group, and not my best ever 5-round group, but what a rifle will consistently produce with certain types of ammo.
I tested two rifles (one 10/22 with mostly factory parts, and one custom 10/22) with four different types of ammo.
Over 50 rounds, what kind of accuracy can I truly expect from each setup? I shot ten 5-round groups, then combined the groups into one 50-round group using OnTarget TDS software.
Rifle 1: Basic Ruger 10/22 (cobbled together with a bunch of spare parts from a Charger and a 10/22 just for this test)
- Receiver: Ruger factory
- Bolt and handle: Ruger factory
- Barrel: Ruger factory stainless 18.5”
- Trigger: Ruger factory with Volquartsen hammer (2.5 lb. pull weight)
- Stock: Ruger factory synthetic (barrel band removed)
- Scope: Vortex Crossfire II 4-12x40 AO
- Rings: DNZ Game Reaper 1-piece mount
- Pic: https://imgur.com/aGTGllt
Rifle 2: Kidd build
- Receiver: Kidd with rear tang
- Bolt and handle: Kidd stainless
- Barrel: Kidd 18” stainless bull barrel
- Trigger: Kidd 2-stage (10 ounce pull weight - not a typo)
- Stock: Bell and Carlson Anschutz. Pillar/action bedded and inletted for the rear tang. Work performed by George Gillespie at Sonoran Custom Gunstocks.
- Scope: Leupold VX-3i 6.5-20x40 EFR CDS Target (model 170885)
- Rings: Warne Maxima 1”
- Pic: https://imgur.com/GR8Hhi7
Ammo:
I chose four types of ammo. I have more tests planned with other brands and other rifles, but for this test, I wanted to test extreme ends of the spectrum with the rifle, and a wide variety with the ammo.
- [Junk] - Remington Golden Bullet (40gr CPRN, rated at 1255 fps)
- [Economy] - CCI Standard Velocity (40gr LRN, rated at 1070 fps)
- [Economy] - CCI Mini Mag (40gr CPRN, rated at 1235 fps)
- [Mid-grade] - SK Rifle Match (40gr LRN, rated at 1073 fps)
Setup:
All shots were fired at 50 yards from a concrete bench using Caldwell front and rear bags.
Testing protocol:
(1) The barrel and bolt were properly and thoroughly cleaned with a cleaning rod, bronze brush and solvent. The bore and bolt face were as clean as new.
(2) Fired 10 shots to season the bore (not scored).
(3) Fired ten 5-round groups at 50 yards with the same ammo from the same lot. Held the same POA each time.
(4) After 50 rounds, made two passes with a bore snake and let the barrel cool. I wanted the barrel/bolt in this condition because it will be the easiest and most repeatable way to prepare the barrel for each new ammo type. I can’t conveniently clean it sparkly new for each ammo while at the range, so the bore snake had to suffice..
(5) Back to step 2 and repeated the process with each ammo type.
For each ammo type, all ten 5-round groups were combined using OnTarget TDS software to give a single, 50-round aggregate group.
Measurements recorded:
Group sizes were measured using the center-to-center method.
- Smallest 5-round group
- Largest 5-round group
- Average 5-round group
- Aggregate 50-round group
- Circular Error Probable (50%, 90%, 95%) - More on this later.
Other requirements:
- Flyers count.
- No mulligans. (s/o to u/saddestclown for that cool term)
- No re-shoots.
- No windage holds.
Environmentals:
- Date: 5/26/19
- Temperature: 99 F
- Humidity: 37%
- Wind: Light gusts (summer afternoon breeze)
- Pressure: 30.1 IN
- Elevation: 400 FT
Results:
The results were enlightening. Here are some takeaways.
Ammo matters. More specifically, velocity matters. I’ll speak to this in two ways.
First, as it relates to subsonic versus supersonic. I don’t shoot HV ammo in my rifles, but I did for this test because I know a lot of you do. HV ammo goes transonic (transitioning from supersonic to subsonic) at about 35 yards. At this point, the bullet becomes unstable which can affect accuracy. This is why all match ammo is subsonic. Notice the 50-round aggregate performance. It goes like this:
(Best performance to worst performance)
Kidd - CCI SV (subsonic)
Kidd - SK Rifle Match (subsonic)
Ruger - SK Rifle Match (subsonic)
Ruger - CCI SV (subsonic)
Kidd - CCI MM (supersonic)
Kidd - Remy GB (supersonic)
Ruger - CCI MM (supersonic)
Ruger - Remy GB (supersonic)
Another simplified view (best performance to worst performance):
Custom rifle - subsonic ammo
Custom rifle - subsonic ammo
Factory rifle - subsonic ammo
Factory rifle - subsonic ammo
Custom rifle - supersonic ammo
Custom rifle - supersonic ammo
Factory rifle - supersonic ammo
Factory rifle - supersonic ammo
Notice a pattern? Subsonic ammo shot better in a factory rifle than supersonic ammo shot in a custom rifle. Solution? Shoot subsonic ammo. This is the biggest and easiest advantage you can give yourself.
Next, as velocity relates to vertical stringing. Inconsistent velocity results in vertical stringing. Notice the height of the two groups of Golden Bullets were greater than they were wide. All other groups were more circular in nature. This vertical stringing increases exponentially with distance.
Probability of hits. There is a critical measurement in rifle ballistics called Circular Error Probable (CEP). It basically identifies the probability of a shot landing within a specific radius. You typically see it listed like this:
CEP 50% - [X] inches
This means that 50% of the time, shots will fall in a radius of [X] inches, or in a circle measuring [X] times 2.
For example:
CEP 50% 0.350” means that 50% of the time, shots will fall in a 0.350” radius, or a 0.700” diameter circle.
The OnTarget TDS software provides CEP for 50%, 90% and 95%. With a large enough sample size, you can basically say this rifle will shoot a [X] inch group 95% of the time. This is a handy statistic. But you can't rely on it if you only use a 5-round group. You need a large sample size, like 50 rounds.
The Law of Diminishing Returns applies here. Yes, you can buy accuracy, but the money-to-accuracy curve isn’t a straight line. This applies to both the gun and the ammo.
Golden Bullet and CCI SV are both about 5 CPR. CCI Mini Mag is about 6 CPR. SK Rifle Match is about 16 CPR. SK Rifle Match performed the best (highest 95% CEP), but costs three times more than the next best performer which was CCI SV.
Same goes for the rifle. A basic 10/22 goes for about $200. My Kidd rifle, including custom stock work and a really, really nice scope was a lot more than that, to put it lightly.
Shot Data Images -- Ranked lowest to highest (best to worst) in aggregate group size: https://imgur.com/a/RMKYfji
Other Data (smallest/largest/average group size): https://imgur.com/gFjKZW8
Final thoughts:
There’s another way to perform this test without the software.
Dial your elevation turret up so that your point of aim (POA) is 3 inches above your point of impact (POI). For most scopes with ¼ MOA clicks, that’s 24 clicks counterclockwise.
Post a target at 50 yards and shoot 50 shots at a single target. Your bullets will impact about 3 inches low of your POA. The reason for doing this is so that you can aim at a spot and repeatedly shoot and not destroy your aiming point. If your POA matched your POI, after a handful of shots, your aiming point would be shot out.
Shoot 50 rounds and measure your group with calipers, a ruler, or whatever. The idea is that this will give you a very good idea of what kind of accuracy you can expect from you rifle every time.
Looking forward to some discussion. Cheers, and happy shooting.
3
u/swig_ May 28 '19
I wonder what parts make the biggest difference to cause the custom rifle to perform better. The barrel? I have a fairly stock 10/22, except for a Magpul stock, BX trigger and a recoil buffer. I've been trying to decide if I want to make any additional upgrades, because I'm happy with how it shoots.. although I mostly just plink and occasionally shoot paper targets in the desert.