Does anyone have any links to the military testing results of the URGI?
I just attended another Armorers course and was told the URGI bolts lasted 4 times longer and the barrels lasted twice as long?
Looking for some actual data...
Does anyone have any links to the military testing results of the URGI?
I just attended another Armorers course and was told the URGI bolts lasted 4 times longer and the barrels lasted twice as long?
Looking for some actual data...
Longer than what?
The bolts and barrels are standard items.
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Longer than what?
The bolts and barrels are standard items.
Sent from my iPhone using Tapatalk
The URGI that was submitted as a M4 A1 replacement had hammer forged mid lengths and a proprietary bolt. That version was not selected as a replacement.
There are some interesting posts on light fighter about the URGI testing and especially when used with a suppressor and M3 PMAG.
To paraphrase, reliability was very good.
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I never found a straight answer on the condition of the M4A1s they compared them to.
Were they fresh rebuilds too, or had they been used already?
The URGI that was submitted as a M4 A1 replacement had hammer forged mid lengths and a proprietary bolt. That version was not selected as a replacement.
The barrels are DD middies, I assume CHF. Wasn’t aware that a proprietary bolt was ever considered.
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There are some interesting posts on light fighter about the URGI testing and especially when used with a suppressor and M3 PMAG.
To paraphrase, reliability was very good.
Sent from my iPhone using Tapatalk
Do you have a link? Wasn't able to find it over there in the search.
https://soldiersystems.net/2018/05/14/nswc-crane-carbine-mid-length-gas-system-testing-shows-increased-performance/
Here's the test. I said something about this in another thread that I think is pertinent here:
There are several things that make me raise an eyebrow at this test.
1. What state were the standard M4A1 rifles/uppers in? Were they brand new production, or were they just used guns taken off the rack? Previous military tests have been notorious for using clapped out old M4s (ie, the sand tests in 2007)
2. They were using M855A1, an insanely high pressure round. Compared to reliability figures done by the Army in 2009 showing the M4A1 having 3600 Mean Rounds Between Stoppages in a baseline reliability test, even the midlength in this test did rather poorly. Many government weapons contracts require at least 2000 MRBS. How would this test have gone if they were using a round that the weapons were actually designed for that isn't damn near proof pressures, rather than one that isn't compatible with any of our NATO allies' rifles and even many of our own (M27 IAR)?
3. Non-military are not using M855A1. I suspect that in certain conditions with certain ammo (.223 pressure), the 14.5" Mid could possibly be undergassed under certain circumstances. Granted, that's just speculation on my part.
4. They should've tested the CHF barrel variable and midlength gas system variable separately. Was the longer barrel life due to the gas system length or the CHF barrel? Or some combination? If so, to what degree each? Testing them separately could've told us that.
When you have an Army figure from 2009 of 3600 MRBS, and then see the results of this test, something just doesn't add up. Both the midlength and the carbine length did significantly worse than previous M4A1 tests using M855.
https://soldiersystems.net/2018/05/14/nswc-crane-carbine-mid-length-gas-system-testing-shows-increased-performance/
Here's the test. I said something about this in another thread that I think is pertinent here:
There are several things that make me raise an eyebrow at this test.
1. What state were the standard M4A1 rifles/uppers in? Were they brand new production, or were they just used guns taken off the rack? Previous military tests have been notorious for using clapped out old M4s (ie, the sand tests in 2007)
2. They were using M855A1, an insanely high pressure round. Compared to reliability figures done by the Army in 2009 showing the M4A1 having 3600 Mean Rounds Between Stoppages in a baseline reliability test, even the midlength in this test did rather poorly. Many government weapons contracts require at least 2000 MRBS. How would this test have gone if they were using a round that the weapons were actually designed for that isn't damn near proof pressures, rather than one that isn't compatible with any of our NATO allies' rifles and even many of our own (M27 IAR)?
3. Non-military are not using M855A1. I suspect that in certain conditions with certain ammo (.223 pressure), the 14.5" Mid could possibly be undergassed under certain circumstances. Granted, that's just speculation on my part.
4. They should've tested the CHF barrel variable and midlength gas system variable separately. Was the longer barrel life due to the gas system length or the CHF barrel? Or some combination? If so, to what degree each? Testing them separately could've told us that.
When you have an Army figure from 2009 of 3600 MRBS, and then see the results of this test, something just doesn't add up. Both the midlength and the carbine length did significantly worse than previous M4A1 tests using M855.
A few things about reading reliability figures, particularly the 2007 system assessment (aka the Sand and Dust Test):
1. What were the tests for? The test was primarily to establish a system baseline and establish a testing and statistical reduction of the data for future procurement. Normally, when you test, you have a control weapon, and so you need twice as much ammunition, twice as many testers, or twice as much time. Now with the base line test, they can test the weapons in the same manner, under the same conditions and reduce the data in the same manner and get comparable results, at reduced cost. It was also used to compare the Current M16/M4/M249 reliability to the OICW reliability requirements.
2. People like to pull a single MRBS (like 3600) and run with it. It's not quite that simple. First, this report breaks down reliability in to two categories, Class I & II and Class III. Class I stoppages are those that can be cleared in less than 10 seconds, Class II stoppages are those that take longer than 10 seconds but can be cleared with basic issued tools (BII), and Class III stoppages are those that cannot be cleared by the operator, and require the weapon to be evacuated to a maintenance activity (normally the unit armorer). Second, this report further broke down the reliability by new or re-manufactured weapons. So, for the M4, you have four MRBS numbers: Class I & II/ new, Class I & II/rebuilt, Class III/new, Class III/rebuilt. Then to further complicate things they have the 90% confidence level number for each MRBS.
Where they got 3600 from, I don't know, but it looks like they just pulled the lowest number on the chart. The listed MRBS for the M16/M4 class of weapons ranges from 3600 to 4800. Further, barrel failure, i.e., a worn out barrel, is technically a Class III stoppage, as keyholing bullets cannot be corrected by the operator, but are generally a scheduled repair, you can recalculate the Class III MRBS, not including barrel numbers, which just about doubles the Class III MRBS numbers.
3. While you are correct in wondering about comparing new vs used, used weapons are rarely, if ever, used in testing. Usually, your choice is new or rebuild. While there is a difference of a hundred or so rounds in the MRBS numbers, new vs rebuilt is not a big difference.
4. In 2015, this test was redone with M855A1 ammunition, because obviously, new ammunition, new reliability figures. But there was an added complication, the M4 was in the middle of a PIP upgrade, so you now have numbers for new build PIP weapons and rebuild PIP weapons with both Class I &II and Class III stoppages. M27 data was also added. Again most people just pull the lowest number.
I have pulled data from this report on numerous occasions in reference to bolt life. Just to be clear in these cases, I did not include the first bolt failure of rebuild weapons as you don't know how many rounds that bolt had on it when it left rebuild, but all subsequent failures do count.
5. Testing of CHF barrels independent of all other variables has been done, therefore not necessary to do again. Barrels made from the same material but either CHF or button rifled showed no difference in usable life. Improved materials are the reason for improved barrel life.
Previous military tests have been notorious for using clapped out old M4s (ie, the sand tests in 2007)
No.
That test used only new and rebuild weapons. And the result from each were segregated so they know what reliability degradation you get from rebuild weapons, and it's not much.
And one last thing, about NSWC Crane, they tend not to release their entire reports, just their Power-Points. Power-Point presentations are like TV commercials, they are made for one of two reasons, 1) to justify funding for a project, or 2) justify the existence of a facility. So, raw data for independent analysis is non-existent, and the Power-Point has a slant towards funding whatever is offered.
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