Ammunition guide for the 457

Updated 2026-10-11 · Covers 22 LR, 17 HMR and 22 WMR (457 barrels are swappable between calibers, see the barrels hub). Group sizes are quoted exactly as each source reported them; we don't average across sources or invent numbers.

The short answer

Start with a box each of SK Standard Plus, CCI Standard Velocity and Lapua Center-X. Shoot them with the method below; buy a case of the best lot. The cheaper training loads often come close to match ammo in factory rifles, and lot matters as much as brand.

What tends to shoot best

Tier	Loads	What the evidence says	Conf.
Bulk / plinking	Federal Automatch, other bulk	Fine for fun and function checks; owner tests show larger groups than training/match loads.	low
Training (best value)	SK Standard Plus, CCI Standard Velocity, Norma Tac-22	Repeatedly near the top in owner tests on both rifles at roughly half the cost of Center-X; lot-dependent.	med
Match	Lapua Center-X / Midas+, SK Rifle Match / Long Range Match, ELEY Match/Tenex, RWS R50	Best average groups in press and owner tests; a well-chosen lot matters more than the label.	med
Hunting .22 LR	CCI Mini-Mag HP (high velocity)	Hollow-point hunting load; .643 in avg in one T1x test. Check local game rules.	med
Suppressed	Standard-velocity/subsonic (CCI SV, SK, Center-X); CCI Quiet-22 at short range	Keep below ~1,125 fps to avoid the supersonic crack; bolt guns don't need cycling power.	med
.17 HMR	CCI GamePoint 20 gr, Hornady 17 gr V-Max / 20 gr XTP	Press tests show ~.4–.6 in @50 yd and ~13–15 mm @100 m; .17 HMR is notably lot-sensitive per owners.	med

Reported test results in the 457

One rifle and one lot per row unless noted. Different distances, group counts and measuring methods — compare within a row's test, not across rows.

Load	Tier	Result (as reported)	Test	Conf.	Source
Lapua Midas+	match	9.37 mm c-t-c (avg of eight 3-shot groups)	@50 yd, 457 MTR, owner test with fouling protocol	low	Rimfire Central 457 MTR test
Lapua Center-X	match	9.21 mm c-t-c (same protocol)	same test	low	Rimfire Central 457 MTR test
SK Rifle Match	match	12.53 mm c-t-c	same test	low	Rimfire Central 457 MTR test
Eley Target	match	11.96 mm c-t-c	same test	low	Rimfire Central 457 MTR test
SK Standard Plus	training	avg .551 in (best .343)	five 5-shot groups @50 yd, 457 American	low	Rimfire Central 457 American test
Lapua Center-X	match	avg .553 in (other day .686 in)	same owner, two sessions — shows day-to-day spread	low	Rimfire Central 457 American test
Federal Automatch	bulk	avg .884 in	same owner test	low	Rimfire Central 457 American test
SK Long Range Match	match	under 1 MOA at 100 yd; outperformed an Eley subsonic HP	prone, 5- and 10-shot groups, 457 AT-ONE, press	med	Guns & Ammo 457 AT-ONE review
Lapua Center-X (best tested lot)	match	30-shot group 29.2 mm at 100 m (outside-edge); best lot < half the size of a random lot, Federal Gold Medal and CCI Standard	machine-rest at Lapua RPC, customized 457	med	GunsAmerica: Lapua RPC, Projekt 457
Hornady 17 gr V-Max (.17 HMR)	hunting	15 mm at 100 m (20 gr XTP: 13 mm)	457 Varmint .17 HMR, press test	med	all4shooters 457 Varmint .17 HMR
Hornady 30 gr V-Max (.22 WMR)	hunting	.46 in @50 yd; 1.2 in @100 yd	457 Lux .22 WMR, press test	med	TFB 457 Lux .22 WMR
Remington 33 gr AccuTip-V (.22 WMR)	hunting	about .45–.6 in @50 yd	owner report, 457 WMR	low	Rimfire Central 457 WMR

How SK grades its ammo

SK USA told Guns & Ammo that each production run is sorted by 50 m test-tunnel accuracy: the best 1,073 fps ammunition becomes Rifle Match, then Standard Plus, Pistol Match and Magazine; the 1,106 fps line runs Long Range Match, then Biathlon Sport, then Pistol Match Special. Guns & Ammo 457 AT-ONE review

Lot-to-lot variation

Rimfire accuracy varies by production lot. At Lapua's test center a customized CZ 457's best Center-X lot shot groups less than half the size of a random lot GunsAmerica: Lapua RPC, Projekt 457. Owners report the same with SK Standard Plus — one exceptional lot found from five sampled Rimfire Central: SK Standard Plus lots. Factory test centers exist: Lapua typically tests six to eight lots through your barreled action in a return-to-battery fixture Lapua rimfire test shooting; ELEY screens up to 20 batches at 10 shots, then 30 more from the shortlist for a 40-shot group ELEY batch testing.

How to test ammo yourself

Season and clean first. Start with a consistent bore condition and foul with 10–15 rounds of the lube family you're testing; clean and re-foul when switching between very different lubes Rimfire Central: lot testing & sample sizes.
Buy small samples of several lots (one or two boxes each) and record the lot number from each box Rimfire Central: SK Standard Plus lots.
Shoot at 50 yd first from a solid rest, early or in low wind; ignore the first group after an ammo change Rimfire Central 457 MTR test.
Use enough shots. Ten-shot groups — several per lot — tell you far more than one 5-shot group; one owner guide suggests ~100 rounds per lot at 50 yd before deciding Rimfire Central: lot testing & sample sizes.
Measure consistently (center-to-center or mean radius; don't mix with outside-edge measurements) and note conditions and velocity SD if you have a chronograph.
Confirm at 100 yd if you shoot NRL22/PRS rimfire; then buy a case of the winning lot Ultimate Reloader: getting into NRL22.

Keep the rifle side constant while testing: same action-screw torque (see gunsmithing), same rest, same scope settings.

Subsonic vs high-velocity, and suppressors

Standard-velocity loads (about 1,070–1,085 fps for CCI SV, SK Standard Plus and Norma Tac-22 per the makers) stay under the speed of sound in most conditions; above roughly 1,125 fps the bullet's crack is audible even with a suppressor Angstadt Arms: suppressed .22 LR ammo. A bolt action doesn't need cycling power, so CCI Quiet-22 (710 fps) works but is a short-range load. Chronograph through your barrel — velocity varies with barrel length and temperature.

Chamber, barrel and cleaning factors

457 barrels vary by model (sporter vs heavy); a factory heavy barrel or aftermarket prefit can change which loads it likes — re-test after any barrel swap.
New barrels can change preference as they foul in; one owner's best load shifted between sessions Rimfire Central 457 American test.
Cleaning resets the bore; fire fouling shots before scored groups. ELEY suggests roughly 90–100 rounds between competition cleanings ELEY: how often to clean; see our maintenance schedule.

Where to buy (affiliate-ready)

Product links go to retailers and may be affiliate links; we may earn a commission. Prices as of Oct 2026. Affiliate disclosure

Load	Cal.	Tier	Velocity (maker)	Price seen
CCI Standard Velocity 40 gr LRN (0032)	.22 LR	training	1070 fps	check price	At MidwayUSA
SK Standard Plus 40 gr LRN	.22 LR	training	1073 fps	$81.99 / 500	At MidwayUSA
SK Rifle Match 40 gr LRN	.22 LR	match	1073 fps	check price	At MidwayUSA
Lapua Center-X 40 gr LRN (500 brick)	.22 LR	match	—	$187.99 / 500	At Brownells
Norma TAC-22 40 gr LRN	.22 LR	training	1083 fps	check price	At MidwayUSA
Federal Gold Medal Target 40 gr (711B)	.22 LR	training	—	check price	At MidwayUSA
CCI Mini-Mag 40 gr HP (100)	.22 LR	hunting	—	check price	At MidwayUSA
CCI Quiet-22 40 gr LRN (500)	.22 LR	suppressed	710 fps	check price	At Brownells
CCI/Hornady 17 HMR 17 gr V-Max	.17 HMR	hunting	2550 fps	check price	At MidwayUSA

Buying ammo online: federal law bars licensed dealers from selling rifle ammunition to anyone under 18 18 U.S.C. 922; some states add rules (e.g. California's ammunition-vendor law California Penal Code (ammunition)). MidwayUSA ships ammunition by UPS Ground only MidwayUSA shipping info. Amazon doesn't sell ammunition Amazon weapons policy. Commission note: programs can set product-level rates, including 0% on specific items AvantLink item-based commission; MidwayUSA's AvantLink program is reported at 5% MidwayUSA AvantLink program summary (third-party) — confirm ammo terms in each program before relying on it.