Blowback Bolt Weight - Revision history

Johndoe: /* Advise */

2026-02-06T16:15:06Z

Advise

← Older revision		Revision as of 11:15, 6 February 2026
Line 85:		Line 85:

	For .22LR, a common blowback mass is 200-220g.		For .22LR, a common blowback mass is 200-220g.

			Always err on the safe side.

			The worst thing that can happen if you choose a heavier weight compared to a lighter one is that your gun won't cycle or eject reliably because the bolt doesn't move far enough backward or not quick enough to throw out the old case or it won't cycle reliably with low-powered ammo like subsonic ammo.

			However, if you choose a bolt that's too light for the highest powered commercial ammo of a certain caliber, it is certain that you'll have excessive wear on your components because of a very fast moving bolt, as well as the possibility of a serious detonation out of the chamber.

Johndoe: /* Bolt Weights */ Fix typo

2026-02-06T16:09:11Z

Bolt Weights: Fix typo

← Older revision		Revision as of 11:09, 6 February 2026
Line 71:		Line 71:
	\|9x19		\|9x19
	\|Sterling		\|Sterling
	\|~~210~~		\|610
	\|Open Bolt		\|Open Bolt
	\|}		\|}

172.71.172.24: /* Advise */

2026-02-06T09:29:05Z

Advise

@@ Line 1: / Line 1: @@
 == Introduction ==
 == Bolt Weights ==
@@ Line 65: / Line 82: @@
 It is also a common flaw in DIY guns to have, sometimes vastly, underweight bolts. A bolt too light is not only dangerous because it might open the chamber when there's still high pressure inside, but it also increases wear because the bolt moves back too fast.
-For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor.
+For 9x19, a common bolt blowback mass is around 650-700g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor.
 For .22LR, a common blowback mass is 200-220g.

Johndoe: /* Bolt Weights */

2026-02-06T08:18:11Z

Bolt Weights

← Older revision		Revision as of 03:18, 6 February 2026
Line 50:		Line 50:
	\|Gevarm A6		\|Gevarm A6
	\|205		\|205
			\|Open Bolt
			\|-
			\|9x19
			\|Sterling
			\|210
	\|Open Bolt		\|Open Bolt
	\|}		\|}

Johndoe at 08:11, 6 February 2026

2026-02-06T08:11:49Z

← Older revision		Revision as of 03:11, 6 February 2026
Line 1:		Line 1:
	== Introduction ==		== Introduction ==

			== Bolt Weights ==
			This list contains the '''measured weights''' of actual production-gun bolts that are proven safe.

			The weights refer to the complete bolt assembly '''without''' the charging handle and recoil spring.
			{\| class="wikitable"
			\|+Blowback SMG Bolt Weights
			!Caliber
			!Gun
			!Bolt Weight (gram)
			\|Action Type
			\|-
			\|9x19
			\|Sten MK2
			\|630
			\|Open Bolt
			\|-
			\|.45 ACP
			\|M3 "Grease Gun"
			\|880
			\|Open Bolt
			\|-
			\|9x19
			\|Uzi
			\|660
			\|Open Bolt
			\|-
			\|9x19
			\|F1
			\|700
			\|Open Bolt
			\|-
			\|9x19
			\|Owen
			\|670
			\|Open Bolt
			\|-
			\|9x19
			\|MP40
			\|650
			\|Open Bolt
			\|-
			\|.22LR
			\|Voere 2005
			\|210
			\|Open Bolt
			\|-
			\|.22LR
			\|Gevarm A6
			\|205
			\|Open Bolt
			\|}

	== Advise ==		== Advise ==

Johndoe at 17:35, 5 February 2026

2026-02-05T17:35:24Z

← Older revision		Revision as of 12:35, 5 February 2026
Line 3:		Line 3:
	== Advise ==		== Advise ==
	The best advise for designing a safe and secure bolt is to look what professional companies have designed.		The best advise for designing a safe and secure bolt is to look what professional companies have designed.

			Many of the formulas that circulate on the web are not quite correct.

			It is also a common flaw in DIY guns to have, sometimes vastly, underweight bolts. A bolt too light is not only dangerous because it might open the chamber when there's still high pressure inside, but it also increases wear because the bolt moves back too fast.

	For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor.		For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor.

	For .22LR, a common blowback mass is 200-220g.		For .22LR, a common blowback mass is 200-220g.

Johndoe: Created page with "== Introduction == == Advise == The best advise for designing a safe and secure bolt is to look what professional companies have designed. For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor. For .22LR, a common blowback mass is 200-220g."

2026-02-05T17:33:43Z

Created page with "== Introduction == == Advise == The best advise for designing a safe and secure bolt is to look what professional companies have designed. For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor. For .22LR, a common blowback mass is 200-220g."

New page

== Introduction ==

== Advise ==
The best advise for designing a safe and secure bolt is to look what professional companies have designed.

For 9x19, a common bolt blowback mass is around 650g. This includes the bolt handle and attachments to the bolt that are part of the moving mass, i.e. the firing pin and the extractor.

For .22LR, a common blowback mass is 200-220g.