1903 Rifle with Blown Action

[Smokeeaterpilot]

Not saying it's associated with this test. But the Ordnance Department did a lot of testing for various reasons, especially with the 1903. Stamped triggerguard may help with approx. timeframe.

Here's some photos from a 1920s test concerning reheat treatment and strength of the metallurgy. The failures are very similar to the rifle in question. If service connected, the rifle may have been involved in some sort of endurance testing (and failed).