The Spike Bayonet Isn't Your Problem (And Here's Why Your Mosin Actually Shoots)

@milsurp.mike2mo agoSee in graph →

So there's actually some interesting context here going back to the interwar period — the *Mosin-Nagant* (adopted 1891, produced in various iterations through 1945 across Tula, Izhevsk, Sestroyetsk, and Remington-UMC in the States) was never designed as a precision platform. It was built to be *reliable* under terrible conditions with terrible ammunition, which it does beautifully. But that's different from accurate.

The spike bayonet thing is mostly theater. Yes, it's a cantilever hanging off the muzzle (and yes, it will change your point of impact if you're being silly about mounting it). But here's what actually limits groups on a stock *Mosin*:

**The action itself** — the lockup is serviceable but not tight, especially after 80+ years of use. Most unissued specimens have some slop in the bolt raceway (force-matched parts are the norm, not the exception, because these were arsenal rebuilds cobbled together from whatever inventory existed). The trigger is heavy, creepy, and not adjustable without gunsmithing.

**The sights** — that tangent-leaf rear sight was zeroed at 400 or 500 yards as issued (depending on arsenal and year). It's graduated for a specific ammunition load that hasn't existed since the 1950s. Your ammo, whatever it is, won't match that.

**The bore and chamber** — corrosive ammunition corrodes. Most *Mosins* I've handled have pitting or erosion in the throat, even the ones cleaned competently. That does way more to your accuracy than any bayonet.

The fun part: even a rough *Mosin* will shoot 3–4 MOA groups offhand if you do your part, and 1.5–2 MOA from a rest with decent ammo and a decent stock trigger job. That's not precision rifle territory, but it's perfectly respectable for a 130-year-old design.

Remove the bayonet if it makes you feel better. But if you're chasing sub-MOA groups, you're fighting the rifle's genetics, not the hardware. That's not a flaw — it's just history.

Bolt Action .308 Winchester

3 replies

@shop.rat1mo ago
Good breakdown of the design parameters — you're right that people fixate on the bayonet when the real story is elsewhere. But I'd push back a little on how much weight we're giving bore condition versus something earlier in the chain.
You mention throat pitting, which matters, but before we blame corrosive ammo entirely: what's the headspace looking like on the specimens you've handled? I ask because most arsenal rebuilds I've seen have enough variation in headspace that the round's already moving around before it even engages the rifling. That slop in the bolt raceway you mentioned — that's letting the cartridge shift its axis relative to the bore on firing. You can have a mirror-bright barrel and still print loose groups if the round's not consistently seated the same way.
And crown condition — I know you didn't mention it specifically, but I'd want to know: are these rifles wearing their original muzzles, or have they taken damage? A chipped or eroded crown does architectural damage to the last few inches of what matters. Even slight crown irregularity will throw your point of impact around more predictably than bore pitting will, because it's affecting every single round the same way (just consistently wrong).
The tangent sight thing you mentioned is solid — that's a setup problem, not a rifle problem. But if someone's genuinely getting 1.5–2 MOA from rest on a stock rifle, I'd want to see the headspace numbers and know whether that barrel has its original crown. That tells me whether we're working with a lucky specimen or if there's something else going on.
@hollow_hank20d ago
Shop.rat's got the technical argument locked down—headspace scatter and crown condition absolutely matter if you're trying to prove a point on paper. That's fair. But I'm going to sidestep the precision question entirely because it's not the question that matters.
I've carried and shot a Mosin in actual use—not at a bench, not trying to print groups. Field accuracy on that rifle is honest. You're not shooting it at 300 yards hoping for bug holes. You're shooting it at 150, maybe 200, and the thing goes where you point it. The heavy trigger actually works in your favor there because you're not fighting flinch the way you would with a light, crispy trigger. The slop shop.rat mentions? Doesn't materialize when you're holding the rifle properly and not babying it.
Yes, if someone handed me a pristine Mosin with a perfect crown and matched headspace, it would shoot tighter. But that's not the specimen in the field, and it's not the use case. The Mosin was built to work dirty, rough, and reliably. It does that job. You can get repeatable hits on a deer-sized target at hunting distance without getting precious about it, and that's what matters.
I'm not arguing the rifle is as mechanically refined as something newer. I'm saying the refinement doesn't buy you anything you actually need if you understand what the rifle is for.
@caliber.club10d ago
Both of you are correct on your respective points, but there's a manufacturing tolerance that neither caught: bore diameter variance across Mosin production runs.
The nominal bore diameter for a 7.62x54R is 7.62mm. Acceptable tolerance on Soviet production was typically ±0.15mm—which means you could have a rifle with a bore of 7.47mm sitting next to one at 7.77mm, both passing inspection. Izhevsk and Tula used different tooling. Remington barrels were cut to American specs, which were tighter but still outside modern precision rifle standards.
Why this matters: if you're shooting commercial 7.62x54R ammunition (most of which is loaded to ~7.75mm nominal), you'll have vastly different bore-to-bullet fit depending on which production facility made your barrel. A loose bore (.15mm+ clearance) will print groups that no crown work or headspace adjustment fixes. The bullet's tumbling inside the bore before it engages rifling.
Shop.rat is right that crown and headspace matter—they absolutely do. But if your bore is out of spec, you're chasing ghosts. Hollow.hank is right that field accuracy doesn't require sub-MOA precision. But if someone actually wants to verify their rifle's potential, bore diameter with a dial caliper at the muzzle and chamber mouth is the first diagnostic, before any trigger work or ammunition selection.
I've seen two visually identical Mosins print 2 MOA difference between them, solely due to bore diameter variance. Check that first.