Feeding It — the Load-Out

Introduction

The question that started this dive was a practical one: a daily .22 round for rabbits and squirrels and for target practice, that lives in a hot truck, and that does not punish a take-apart suppressor. Shots are taken inside 30 yards. The rifle has a KIDD drivetrain including the guide rod and spring kit.

That is a narrow enough set of constraints to have an actual answer rather than a survey.

⭐ THE DECISION: CCI Clean-22 Sub-Sonic, 40 gr at 1,070 fps, as the single load — with the KIDD green (−10%) recoil spring installed and left alone. One load, one spring, one magnification setting, one zero.

⚠ That is not the load the ballistics alone would pick, and the reasoning is worth following — it is a case of a system constraint beating a component optimum, which is the sort of thing a build log should record rather than tidy away.

The rest of this volume is why, and what the popular advice gets wrong on the way there.

4.1 Why subsonic wins here specifically

Not because subsonic is better. Because the constraints delete the argument for high velocity.

Under 30 yards, trajectory is not a variable. The flatter arc of a 1,235 fps load is the main thing you buy with high velocity, and at 25–30 yards from a 50-yard zero the difference between a 1,070 fps and a 1,235 fps load is a fraction of an inch. You are paying for a benefit that does not exist at the distance you shoot.

What you are giving up by going supersonic is the entire point of the suppressor. A supersonic bullet makes its own sonic crack downrange, and no can silences that. The suppressor deals with muzzle blast; the bullet handles the rest by itself. Staying subsonic is what converts an expensive registered object into a genuinely quiet rifle.

And the rifle is already set up for it. The .22 Rimfire dive’s own conclusion is that this 10/22 cycles a 1,070 fps load as delivered, and the KIDD guide rod kit ships three interchangeable springs — so if a slower load ever needs help, the purpose-built answer is already in the parts drawer rather than a part to go buy.

Terminal effect at this range is adequate and the discipline is the same either way. Every subsonic candidate below carries 94–102 ft·lbf at the muzzle — a spread too narrow to choose on. On rabbits and squirrels inside 30 yards that is sufficient with head and neck shots, which is the shot to be taking regardless. 🔴 A solid round nose does not expand, and body-shooting small game with a solid is how animals are lost.

4.2 The spring, now that one load is chosen

⭐ Choosing a single load is what makes the spring decision trivial, and this is the real payoff of standardising. The .22 Rimfire dive already recommends running one load in both suppressed and unsuppressed configurations, because it deletes an entire axis from the BDC-reticle problem — the trajectory stops changing, so only a constant zero offset remains.

Committing to 1,070 fps deletes a second axis at the same time: the spring stops needing to change either. Install the subsonic spring, and leave it in.

🔴 The correction, because the popular version of this advice is self-contradictory. It is commonly claimed that a lighter recoil spring buys both more reliable cycling of low-velocity ammunition and less wear on the receiver. Those pull in opposite directions. A lighter spring resists the bolt less, which is what helps it cycle — and that same reduced resistance lets the bolt arrive at the rear of its travel faster and hit harder. You do not get both.

✅ The part that actually protects the receiver is the bolt buffer, and this rifle has one. The KIDD bolt buffer replaces the factory pin and is the correct answer to bolt battering. The recoil spring is a cycling tuning device; the buffer is the protection device. Keep the jobs separate and both decisions get easier.

4.2.1 The spring colours — read off the kit instructions

✅ Settled from the kit’s own documentation, which is a better source than anything published online:

Table 1 — ✅ Settled from the kit's own documentation, which is a better source than anything published online

Spring	Tension	Use
White	Standard	The baseline
Red	+10%	Hotter rounds — 17 Mach 2, hyper-velocity
🟢 Green	−10%	🟢 Subsonic. This is the one that goes in.

🔴 And this is where the popular advice would have actively hurt you. The widely circulated version of this recommendation names the red spring as the subsonic spring. Red is the +10% spring — the stiffest of the three. Installing it to cure short-cycling on a 1,070 fps load would make the exact problem it is supposed to fix worse, and it would do so in a way that reads as “the ammunition is no good” rather than “the spring is wrong.”

The direction is the thing to remember, and it is not arbitrary: less powder needs less spring to work against. Subsonic → green → less tension. Hotter → red → more.

⭐ A useful convergence worth noting. The .22 Rimfire dive’s own footnote on this — written before anyone had the kit in hand — records the community consensus fix for subsonic cycling in a suppressed 10/22 as “a ~10% lighter recoil spring,” and flags it as medium confidence because it was forum consensus rather than a manufacturer figure. KIDD’s kit ships exactly ±10%. The consensus number and the product turn out to be the same number, which is about as good as confirmation gets for this kind of claim.

4.3 The corrections

The popular guidance on this exact question is wrong in five specific ways, and the corrections are more useful than the recommendation.

1. The velocities get garbled. Clean-22 Sub-Sonic is 1,070 fps, not 1,050. The 1,235 fps load is High Velocity, not “Hyper Velocity” — Hyper is a separate, lighter, faster product. Advice that mixes up which product it is recommending is advice that has not been checked.

2. 🔴 Polymer coating is not heat protection, and this is the important one. It replaces the wax and cuts the lead fouling. It does nothing at all for the propellant, which is the actual heat risk (vol 2). Clean-22 on a dashboard is a worse plan than bulk CCI in the drawer.

3. 🔴 “Keeps your baffles from binding” overstates it. The coating changes what the fouling is made of, not how much fouling there is. Powder and priming residue still go into the can on every shot. The lead fraction — the part that cements a baffle stack — is what drops. The can gets easier to clean, not cleaner for longer. The 300–500 round interval stands, and for an out-of-production suppressor it should be treated as a ceiling.

4. CCI Uppercut is the wrong tool here, and the reason is the opposite of the usual one. It is recommended as the “unwaxed jacketed option for small game.” Its actual specification: 32 gr, 950 fps, 64 ft·lbf at the muzzle, and CCI states it is “velocity optimized for performance through semi-automatic handguns with 2.5- to 4-inch barrels.” It is a defensive pistol round. Out of an 18.5 in rifle it delivers less muzzle energy than an ordinary 40 gr at 1,070 fps — about two-thirds of it. ✅ But CCI’s own product copy is the best sourcing in this whole discussion for the original problem: “unwaxed bullet reduces fouling and improves feeding in all temperatures.” The manufacturer names the symptom exactly.

5. The match-lubricant claim is backwards in the specific. Match ammunition is often described as carrying a “greasy liquid oil or tallow.” ELEY’s own account: match rounds use beeswax-tallow, “softer, thicker and stickier”; semi-auto and recreational rounds use paraffin, harder and higher-melting, chosen because it does not clog a semi-auto. It is a soft wax, not an oil — and the practical direction still holds: match ammunition carries the softest lubricant on the shelf and is the worst choice for a hot truck.

⚠ And one claim not repeated here at all: that Sellier & Bellot Club uses a dry graphite coating rather than wax. The only sourcing found for it was a forum post. It may well be true. It is not established, and it is not going into a recommendation.

4.4 The cost argument, without inventing prices

Ammunition pricing moves too fast to hard-code, but the structure of this decision does not need a price, because of a coincidence worth noticing:

⭐ CCI Standard Velocity and CCI Clean-22 Sub-Sonic are both 40 gr at 1,070 fps. Ballistically they are the same load. The premium buys exactly one thing: the coating — which makes the coating’s value the whole question, cleanly separated from ballistics.

It is not “which load performs better for the money” — they perform the same. It is “is the polymer coating worth the delta?” And for this owner it is, on two counts that have nothing to do with ballistics:

• The melted-box problem goes away entirely. Nothing on the bullet to soften.
• The suppressor is out of production, so anything that reduces the lead fraction going into it is buying insurance on a component that cannot be replaced.

At the volume one rifle actually consumes in a season, that delta is small in absolute dollars. ⚠ Price it yourself before the season — this is a structural argument, not a price quote.

⚠ The same logic transfers to the load actually chosen below, with one caveat. Clean-22 Suppressor has no uncoated twin at identical specification, so the comparison is not quite as clean — but the 200-round box means fewer packages for the same round count, and at a 200-round annual load-out this is a once-a-season purchase, not a running cost. The price argument is close to irrelevant at this volume; the coating argument is not.

4.5 One round for everything — the three-way comparison

Carrying a single load is worth real simplicity: one trajectory, one spring, one magnification setting on the BDC150, one zero offset, one thing to buy. The question is which one earns that slot. Three candidates, and their published specifications settle it more cleanly than opinion does.

Table 2 — One round for everything — the three-way comparison

	CCI Suppressor (957)	⭐ Clean-22 Suppressor (980CC)	Clean-22 Sub-Sonic (934CC)
Bullet	45 gr lead hollow point	45 gr lead round nose	40 gr lead round nose
Muzzle velocity	970 fps	1,000 fps	1,070 fps
Muzzle energy	94 ft·lbf	100 ft·lbf	102 ft·lbf
Lubricant	🔴 Wax	✅ Polymer	✅ Polymer
Rounds per box	50	200	100
CCI on cycling	”Reliable function in suppressed semi-automatic firearms"	"Reliable function in semi-automatic firearms"	"Flawless cycling through semi-automatics”

4.5.1 🔴 A correction to this dive’s first draft

The earlier version of this volume told you to skip Clean-22 Suppressor as the primary, on the grounds that 45 gr at 1,000 fps is the marginal cycling case in a blowback action. That was reasoning from a general principle rather than from this cartridge, and it does not survive contact with the numbers. Bullet momentum — which is what drives a blowback bolt — actually favours it slightly: 45 gr × 1,000 fps is 45,000 gr·fps against the 40 gr load’s 42,800. And CCI states plainly that it delivers “reliable function in semi-automatic firearms.” For a one-round plan it is not the load to skip. It is probably the load to pick.

4.5.2 Energy is not the differentiator — subsonic margin is

All three land within 8 ft·lbf of each other at the muzzle, which is inside the noise for small game inside 30 yards. What genuinely separates them is how much room they leave below the sound barrier — and the sound barrier moves with temperature.

Table 3 — Energy is not the differentiator — subsonic margin is

Ambient	Speed of sound	Margin at 1,070 fps	Margin at 1,000 fps	Margin at 970 fps
90 °F	1,149 fps	79 fps	149 fps	179 fps
59 °F	1,116 fps	46 fps	116 fps	146 fps
32 °F	1,087 fps	17 fps	87 fps	117 fps
20 °F	1,073 fps	🔴 3 fps	73 fps	103 fps

🔴 THE FINDING FOR A YEAR-ROUND SINGLE LOAD: at 20 °F the speed of sound is 1,073 fps, and Clean-22 Sub-Sonic is advertised at 1,070. Michigan rabbit season runs into March. On paper the margin is gone.

⚠ Cold also lowers muzzle velocity, because propellant burns less efficiently — the mechanism behind RWS’s separate biathlon load, which the .22 Rimfire dive covers. So the two effects partly cancel. But “partly cancel” is not a margin, rimfire lot-to-lot variation is comfortably ±30–50 fps on its own, and the whole reason to own a suppressor is not to be guessing about this. The 45 gr loads keep their margin in every column.

⭐ This is a genuine qualification of the recommendation this dive made two volumes ago. For summer plinking at 30 yards the 40 gr load is exactly right — and that is the job it was recommended for. For one round carried year-round in a Michigan truck, its margin closes to nothing on precisely the cold, still mornings when the quiet matters most.

4.5.3 On ballistics alone, the 45 gr wins

Clean-22 Suppressor is the ballistic pick, and on paper it is the only one of the three that does not force a compromise: polymer coating — the entire reason this dive exists — a bullet weight that holds its subsonic margin through a Michigan winter, the same muzzle energy as the others, manufacturer-claimed semi-auto function, and 200-round boxes, which turns out to matter for storage (vol 2).

What it costs you is the hollow point, and that cost is real. CCI says of the 957: “hollow-point bullet consistently expands at low velocities.” Expansion buys forgiveness on imperfect shot placement, which is worth something on rabbits.

🔴 But taking it means accepting a wax-lubricated bullet in a hot truck — the exact problem this entire dive exists to solve — plus 50-round boxes instead of 200. And the .22 LR gives you no way out of that trade: the cartridge uses a heeled, outside-lubricated bullet (vol 2), so it must carry lubricant on the outside unless something replaces it. Clean-22’s polymer is that replacement. Any .22 LR that is not polymer-coated is wax-lubricated, by the architecture of the cartridge.

⚠ The honest framing of the trade: a solid round nose demands head and neck shots. With a scoped, bipod-equipped, KIDD-triggered rifle inside 30 yards, that is the shot you should be taking anyway — but it is a discipline, not an assumption, and choosing the hollow point and managing the wax is a legitimate call rather than a wrong one. What is not legitimate is choosing the solid and then taking body shots.

4.6 🔴 And then the packaging decides it

Clean-22 Suppressor does not ship in a plastic box. It ships in a carton — CCI’s own product announcement described the load as “packed in convenient cartons.” Convenient on a shelf. Disqualifying inside a sealed, desiccated container, for a reason that has nothing to do with rigidity:

⭐ CARDBOARD IS HYGROSCOPIC, AND PAPER IS THE LARGEST DESICCANT LOAD ANYTHING IN THAT BOX CAN CARRY. Paperboard at room equilibrium holds roughly 6–7 percent of its own weight in water. A carton of a few tens of grams is therefore carrying grams of water — against a silica-gel charge whose entire working capacity is a few grams (vol 2).

🔴 A cardboard carton in a desiccated box does not just consume capacity once. It re-wets every time the lid comes off, and the gel spends the rest of its life drying paper instead of protecting ammunition. It is the microfibre-cloth problem from vol 2, an order of magnitude larger, and permanent.

⭐ So the 100-round plastic box turns out to have a third virtue this dive had not articulated. It was praised for being rigid (abrasion) and for not sealing (so the gel can reach the rounds). The third is that it is not hygroscopic — it adds no load to the desiccant at all. Three jobs, and the factory does all of them for free, but only in the plastic packaging.

4.6.1 Why this is a good trade rather than a reluctant one

The 45 gr load’s advantage is bounded. The 40 gr load’s packaging advantage is not.

What the 40 gr actually costs you: on genuinely cold mornings it may make a crack it would not make in July. ⚠ And note what it does not cost you — accuracy. Transonic instability is a problem for a bullet that decelerates through the sound barrier in flight. At 30 yards a .22 has not slowed appreciably: it is supersonic for the whole flight or subsonic for the whole flight, and never transitions. So the penalty is noise on the coldest days, and nothing else — not accuracy, not terminal effect, not safety.

What the carton would cost you is a desiccant system that never quite works, in a box you open regularly, for as long as you own it.

⭐ A bounded, seasonal, cosmetic penalty beats an unbounded, permanent, systemic one. The 40 gr load is the right answer for this truck — and the reason is the box it comes in, not the bullet.

⚠ If the winter crack ever does become annoying, there is an escape that costs nothing: buy the 200-round carton and decant it into a saved 100-round plastic box. You will accumulate empties. The carton never goes in the ammo can.

4.7 What is still unmeasured

This dive ends with four open numbers, all of them cheap to close, and all of them things nobody else publishes:

1. The as-built weight of the rifle — one bathroom scale, ninety seconds (vol 1).
2. Loaded weight of the finished storage stack — the Sheffield box, 200 rounds, spare magazines and filler (vol 1).
3. Drawer versus console temperature over one summer week — two $12 thermometers (vol 2).
4. Empty weight of the Sheffield 12633 — not published; put it on a scale (vol 2).

✅ Two that started open and are now closed: the KIDD spring identification, settled from the kit’s own instructions, and the inner-container question — the factory box already does that job, so nothing needs to be made (vol 2).

⭐ All four are measurements this build can make and the internet cannot. That is the useful half of writing any of this down.

References

• CCI Clean-22 Sub-Sonic — 40 gr LRN, 1,070 fps, 102 ft·lbf, 100/box. CCI Clean-22 Suppressor — 45 gr LRN, 1,000 fps, 100 ft·lbf, 200/box, CCI: “reliable function in semi-automatic firearms.” CCI 22 Suppressor (957) — 45 gr lead hollow point, 970 fps, 94 ft·lbf, 50/box, CCI: “hollow-point bullet consistently expands at low velocities.” CCI Clean-22 High Velocity — 40 gr, 1,235 fps. Polymer coating derived from Federal Syntech; CCI claims a 60–80% reduction in suppressor lead fouling. Manufacturer claim, presented as such.
• CCI Standard Velocity — 40 gr at 1,070 fps; ballistically identical to Clean-22 Sub-Sonic, without the coating.
• CCI Uppercut — 32 gr JHP, 950 fps, 64 ft·lbf at the muzzle; CCI: “Velocity optimized for performance through semi-automatic handguns with 2.5- to 4-inch barrels” and “unwaxed bullet reduces fouling and improves feeding in all temperatures.”
• KIDD guide rod and spring kit — interchangeable tuning springs, white = standard, red = +10% tension, green = −10% tension. ✅ Read directly off the kit’s own instructions — a primary source, and it contradicts the widely repeated online claim that the red spring is the subsonic one. Green is the subsonic spring. The KIDD complete bolt ships with firing pin and extractor and does not include recoil springs.
• ELEY, “Waxing lyrical about .22LR lubricants” — beeswax-tallow is softer, thicker and stickier and is used in match rounds; paraffin is harder, higher-melting, and used in semi-auto and recreational rounds because it does not clog the mechanism.
• CCI Clean-22 Suppressor is packed in cartons, not plastic boxes — described as “packed in convenient cartons” in the product announcement, and confirmed by inspection. Paperboard equilibrium moisture content is roughly 6–7% by weight, which is what makes it a desiccant load rather than merely soft packaging.
• Speed of sound in air computed as a ≈ 49.02 × √(T in °R) ft/s — 1,149 fps at 90 °F, 1,116 at 59 °F, 1,087 at 32 °F, 1,073 at 20 °F. ⚠ Standard atmospheric acoustics; the margins in the table are this dive’s arithmetic against CCI’s advertised velocities, and advertised velocities are nominal.
• ⚠ Sellier & Bellot Club dry-graphite claim — forum-sourced only, not established, deliberately excluded.
• .22 Rimfire, Volume 9, Firearms project — choosing ammunition by job and by gun.
• .22 Rimfire, Volume 10, Firearms project — the 300–500 round rimfire cleaning interval and the polymer-coating discussion.
• .22 Rimfire, Volume 11, Firearms project — the one-load shortcut, the BDC150 magnification exercise, and the two-tier load-out this volume inherits.