Action Army VSR-10 Upgrade Spring

A bolt action is tuned with its spring more than with anything else, and the rating is effectively the whole specification. A higher number means a stiffer coil, more stored energy behind the piston, and a harder push on the BB. Everything else in the rifle then has to cope with it.

Action Army produce this family for the Tokyo Marui VSR-10 and VSR-10 based clones, which covers most of the budget bolt actions sold in the UK. Choosing between the ratings is the only decision here, because the fitment and the build are identical across all four.

Pick by the limit you have to shoot to, not by the biggest number on the list. The M120 is the rating most UK sites will chrono without argument; the heavier ratings assume a dedicated bolt action limit, a minimum engagement distance, and internals built to survive the load.

Specifications

Good to know before you buy

Chrono it before the game, never at it. Most UK sites run a separate single-shot limit for bolt actions alongside a minimum engagement distance. Anything above the M120 is likely to need that classification, so confirm the rule with your marshal and then fit the spring.

No velocity figure is honest in isolation. Two rifles on the same spring can chrono a long way apart depending on cylinder volume, how well the head seals, barrel length and the weight of ammunition. Tell us what you are running and we will give you a realistic bracket instead of a number off a box.

Upgrade the trigger group alongside, not afterwards. The factory sears are cut for the factory spring, and sear engagement is what gives up first under a heavy one. The matching parts sit in our internals section.

The M170 is the odd one out. We can no longer get it and we are not replacing it, so the rating stays on the listing for reference rather than as something we expect to ship.

Frequently asked questions

Which rating should I choose?
Work backwards from your site’s bolt action limit and the BB weight you intend to shoot. The M120 suits most UK skirmish rules; the heavier ratings assume a sniper classification and a rifle built to take them.

What will it chrono at?
There is no fixed answer, which is why none is printed here. The same spring behaves differently across cylinder volumes, seals, barrels and BB weights, and no figure is quoted anywhere.

Will it fit a clone rather than a genuine Marui?
Action Army specify the VSR-10 and VSR-10 based clones, which takes in most of the pattern. If your rifle is an unusual one, ask us before ordering.

Do I need anything else to fit it?
A spring guide makes reassembly far easier, and a heavier rating is worth pairing with a steel sear set. Neither is strictly required to get the spring in.

Why is the M170 described differently?
Because we can no longer get it and we are not replacing it. The other three ratings come in on normal supply; the M170 is listed for reference only.

Is this the same spring sold as four separate listings before?
Yes. We folded the four ratings into one listing so the whole ladder is visible in one place rather than scattered across the catalogue.