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Old February 2, 2013, 09:39 AM   #24
Bart B.
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Join Date: February 15, 2009
Posts: 4,707
There have been several tests of rifles over the years to find out what their "bursting" load (or limit) is. The one that I saw the results of in the late 1960's is overviewed below.

The US Navy Small Arms Match Conditioning Unit used a "low-numbered" M1903 Springfield clamped to a post at their test range in a canyon northeast of San Diego, California. They brought a bunch of Sierra 200-gr. FMJBT match bullets, a variety of powders and lots of primed 30 caliber M72 match cases. Powder measuring and bullet seating tools were also brought to the site as well as tools to use on the rifle, if needed. A string and hook device was put on the trigger and pulled from behind a safety wall as each round was single loaded in the rifle.

Starting with a normal charge of IMR4350 for the bullet, they began shooting them one at a time increasing the charge weight a grain each time until it no longer would fit in the case. Then they moved to IMR4895 with increased charge weights. By now, the bolt was getting stiff to open, but that's all that was noticed. A case full of IMR4895 under that 200 grain bullet required a mallet to smack the bolt handle open easy and fast enough for test speed efficiency. But that load was a testament to that low-numbered M1903's strength that was often stated as very weak.

The crew finally moved to IMR4198 powder and the bolt began to be harder to open. Later with this powder, a pipe wrench had to be used to open the bolt even though it was well greased all over with PlastiLube, a favorite lubricant for the Garands they rebuilt and serviced. And yes, headspace had grown quiet a bit; expected to do so with that low-numbered receiver.

After much ado about powder types and charge weights, that old Springfield finally blew apart with a case fairly full of Bullseye pistol powder. They showed me the box of several of the broken, ragged edged rifle parts in the box they kept them in. The rest of the parts were blown too far from the test stand to be found and are still there to this date; probably.

= = = = = = = =

One could contact SAAMI then ask them about bursting pressure tests on firearms. They may well have excellent information on that.
__________________
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; February 2, 2013 at 09:50 AM.
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