Last thing first: What issue(s) are you having?
The 15-round mags amplify "sensitivities" found in the 10-rounders:
- The magazine MUST!! be held at the correct height in your chassis or stock.
My 2019-vintage rifle is in an MDT BA Comp chassis. When it first came from Vudoo, the non-adjustable mag latch allowed about 3/16" or so of vertical play. This was enough to cause feed failures, especially with the last round or two in my 10-round polymer mags. @RAVAGE88 identified the issue immediately upon seeing it. The end result was my receiving an adjustable latch from MPA; as I understand it, that latch is now standard on the BA Comp chassis.
More broadly, consider the gigantic challenge of stripping a rimmed cartridge with a butter soft bullet off an under-tension stack of cartridges and feeding it into a chamber only a few thousandths of an inch larger in diameter than the bullet, without that bullet suffering scrapes or dents on the way in. Then add the manufacturing tolerances of the plethora of R700 stocks and chassis. It's actually pretty incredible that Vudoos work as well as they do.
- The mags, ESPECIALLY the 15-rounders, MUST be loaded correctly.
Look at the cartridge column in my post's photo (included again here) - notice the alternating pattern of the stack. This is accomplished by pressing the follower button down just enough to slide a round under the feed lips, then release the button. The bullet nose should orient itself just above the front of the mag as shown. If the round is "flat" - not angled as shown and the bullet nose points straight at the front wall of the mag - it's wrong; fix it by tapping the base of the mag gently and/or use a fingernail to pull back and down on the cartridge rim; it should pop into position.
Even if each round is loaded correctly, you may notice two bullet noses on the same side of the mag - no alternation. If you leave that uncorrected, a stoppage is almost guaranteed when the bolt tries to feed that slightly misaligned round.
The 10-round mags have the same requirement; it's just that the column doesn't show the pattern as clearly.
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The "If you know, you know" comment refers to having a 15-round mag with a follower button that makes inserting all 15 incredibly slippery Lapua cartridges in hot weather almost easy. The follower button on ten-round magazines with extensions on them only helps with the first ten, then the last two or five or whatever rounds have to be pushed onto the stack. In August heat, that lube makes manhandling a round onto the stack almost comical.
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This is a good topic and there's some things to share that I believe everyone can get something out of.
First, back in the 2008 to 2010 timeframe as the original thoughts and initial designs were coming together for an AICS form factor rimfire magazine,
THE chassis standard for centerfire was the Accuracy International AICS chassis (for the Rem700 platform) that, of course, used the AICS magazine. There were no other considerable chassis systems or magazines.
So, the original Accuracy International prints were used for the proper physical dimensioning of the magazine receptacle and the physical envelope of the magazine. Of course there was no adjustable latch in the chassis or adjustable catch on the magazine housing. So, it goes without say that because a standard was used, none of these things were used in my magazine housing design or my DBM and there were no feed issues, shaving lead and so forth.
Things move along and the "system" was happy. Then, XLR enters the scene and guess what? Feed issues. Why? Because there was no common "standard" employed and the mag latch was a different dimension than the Accuracy International mag latch. And this problem manifested from there every time another chassis or DBM hit the market.
So, with the permission of Accuracy International, I started contacting the other chassis makers and offering up the actual information that would eliminate the ripple of issues that propagated further across the community each time a new chassis (or DBM) was introduced. The DBM I benchmarked was the Badger Ordnance M5 because Marty hit it out of the park, but he also had a relationship with Accuracy International and has been at this game longer than most.
Sadly, not all the makers were receptive, which is fine, but I'll say that Phil Cashin was the best at having the conversation and responding with a solution that set the stage. I love his chassis systems.
So, when one wonders why there's a need for an adjustable catch or latch, now you know. As I've said before, the mindset associated with copying is different than the mindset used to create (Phil creates). And I want to be clear, there's A LOT of good product out there from A LOT of good sources and I'm not poo pooing anything. Just sharing a perspective that may turn on a few light bulbs....
MB
decrypt.co
