Budget range upgrade (Varmint, American or Synthetic SR in factory stock)
Parts total: ~$197 (as of Oct 2026; excludes rifle, optics, ammo, tax, shipping)
| ID | Part | Price |
|---|---|---|
| C043 | MDT CZ 457 Picatinny base (20 MOA) | $69.99 |
| C050 | CZ 10-rd .22 LR polymer magazine | $39.95 |
| C057 | MKM +3 extension (10+3 = 13 rds) | $17.49 |
| C059 | Anarchy extended mag release Gen II | $24.99 |
| C055 | CZ single-shot adapter | $29.95 |
| C066 | Bolt headspace shim set (triggershims.com) | ~$15 |
| Total | ~$197 |
Why: - A clamp rail fixes dovetail slip (known_issues #7). - The 10-rd mag with +3 extension handles NRL22-length strings. - The single-shot adapter suits benchrest. - Shims are the cheapest accuracy tune (Kurt the Gunsmith measured 0.046 in factory headspace).
Swap: Talley 11 mm rings C044 ($69.95) instead of a rail for a light sporter.
Parts list with retailer links
Every part referenced in this build (including swaps/alternates). Confidence reflects how well fitment/price was verified.
Product links go to retailers and may be affiliate links; we may earn a commission. Prices as of Oct 2026. Affiliate disclosure
| ID | Part | Fits | Price | Confidence | Notes | Link |
|---|---|---|---|---|---|---|
| C043 | MDT Picatinny scope base - CZ 457 (20/30/40/50 MOA) scope mount | CZ 457 (also 455/452 variants) | $69.99 | high Shopify variants | Source: https://mdttac.com/products.json · checked 2026-10-10 | View at retailer |
| C050 | CZ (OEM) 10-rd polymer .22 LR magazine | All CZ 457 (RH unless noted) .22 LR | $29.99 | high Official | re-pointed to program merchant 2026-10-10; price there 29.99 (was 39.95) | Source: https://shop.cz-usa.com/mag-cz-452-453-455-513-512-22-lr-mach-2-10-rd- · checked 2026-10-10 | View at retailer |
| C057 | MK Machining CZ 455/457 +3 extension (5+3 and 10+3 versions) magazine | CZ 455/457 | $17.49 | high Manufacturer page | Nylon 11; uses factory spring/follower Source: https://www.mkmachining.com/product/carbon-fiber-nylon-cz-455-4573-ext · checked 2026-10-10 | View at retailer |
| C059 | Anarchy Outdoors CZ rimfire extended magazine release Gen II magazine | CZ 452/455/457 (not with metal mags) | $24.99 | high Maker page | Works with factory bottom metal Source: https://www.anarchyoutdoors.com/cz-rimfire-rifle-extended-magazine-rel · checked 2026-10-10 | View at retailer |
| C055 | CZ (OEM) Single-shot adapter (.22 LR/.17 M2) magazine | All CZ 457 (RH unless noted) .22 LR | $29.95 | high Official | Manual: protects bullets for max accuracy Source: https://shop.cz-usa.com/single-shot-adapter-cz-452-453-455-512-22lr-17 · checked 2026-10-10 | View at retailer |
| C066 | Triggershims.com (via Kurt the Gunsmith) CZ 457 bolt headspace shims bolt | All CZ 457 (RH unless noted) | <15 (per article) | med Single gunsmith blog with measurements | Measure headspace first; shims reduce firing-pin protrusion Source: https://kurtthegunsmith.com/cz-457-accuracy-the-most-affordable-way-to · checked 2026-10-08 | View at retailer |
| C044 | Talley CZ rimfire steel rings, 11 mm dovetail (22CZRL/22CZRH/30CZRL/30CZRH) scope mount | CZ 452E/455/457/512/513 | $69.95 | high Talley maker page explicitly lists CZ 457 (11 mm dovetail) - fit re-verified 2026-10-10 | Source: https://store.talleyscoperings.com/products/cz-rimfire-steel-rings-for · checked 2026-10-10 | View at retailer |
Before you buy
Part IDs refer to parts.csv (C###). Prices are USD list/street prices on 2026-10-08 and exclude rifle, optic, ammo, tax and shipping. Rifle reference MSRPs (CZ US, variants.csv):
- Scout $649
- American Synthetic SR $679
- American $729
- Lux $749
- Varmint $799
- Pro-Varmint SR $849
- Varmint MTR $999
- AT-ONE $999
- Manners MTR / Precision Chassis MTR $2,399
Rules for every build: - Buy 457-specific stocks, triggers and rails. CZ 455 versions don't fit; only barrels and mags interchange. - Stock screws: 3.5 Nm. Barrel screws: 5.5 Nm, tightened after the mag-housing screw. - Headspace-check every barrel swap. - US threads are 1/2-28; non-US barrels are 1/2-20.