New rifle - AI AXMC in 6.5x47mm Lapua

[WelshShooter]

Another update to keep pushing @MCMXI to get more loading done!

I decided that I would stick with 36gr of N150 and played with the seating depth to find a sweet spot. My current base to ogive length of 2.120" places me a few thou off the lands, so I kept seating the bullets back a further 0.003" until I ran out of virgin brass. I was left with 21 cases so that's 7 sets of 3 rounds.

The velocity didn't really change over the whole range which surprised me. What also surprised me is that my initial load was the most precise! But heck, if I didn't try this then I would've always thought "I wonder if I can tighten these groups up with seating depth". Good to know that group position and spread is almost identical between 2.117" to 2.120" (aside from one flier!) so it tells me that the 123gr Scenar likes to be close to the lands on my rifle.

My zero load was some leftover 37gr loads but I notice some ejector swiping on the case head so I don't think I'd like to continue my testing from 36gr up to 37gr.

I'm not going to muck around with primers as I've got a good supply of magnum primers so I guess it's onto making up a batch of 36gr loads to verify repeatability!

@MCMXI, to keep this on topic, have you taken your rifle to the range lately? If not, what's your excuse?

 

[MCMXI]

@MCMXI, to keep this on topic, have you taken your rifle to the range lately? If not, what's your excuse?

My range is at my house so I have no excuse, other than the need to wrap up other projects that have greater priority. I managed to put some rounds together yesterday and did some shooting, but a big issue cropped up in the form of a 2oz to 3oz second stage on the trigger, and let me assure you, my manual dexterity isn't sufficient to consistently manage such a light second stage. I had at least seven events yesterday when I was taking up the first stage (~2lb-15oz) and set the round off before I was ready. I called Mile High this morning to speak with Adam the lead gunsmith but he's yet to call me back. There's no information in the AI manual re trigger adjustment and only a brief mention that the trigger is " 2-stage, adjustable, set between 3.3lb - 4.4lb, adjustable for reach". My other AI AWs have ~ 2lb-12oz first stages with ~ 1lb second stages which is what I like, kind of similar to the Geissele two-stage triggers in my ARs. I had LabRadar issues too so it was a frustrating day in many ways.

I did shoot some good 5-shot groups and am confident that 38.0gr of Varget is the sweet spot in terms of accuracy, velocity and pressure so I'm going to try different primers and possibly play with seating depth. I need to confirm the best load using H4350 as well. I'll post some results soon.

 

[WelshShooter]

My range is at my house so I have no excuse, other than the need to wrap up other projects that have greater priority. I managed to put some rounds together yesterday and did some shooting, but a big issue cropped up in the form of a 2oz to 3oz second stage on the trigger, and let me assure you, my manual dexterity isn't sufficient to consistently manage such a light second stage. I had at least seven events yesterday when I was taking up the first stage (~2lb-15oz) and set the round off before I was ready. I called Mile High this morning to speak with Adam the lead gunsmith but he's yet to call me back. There's no information in the AI manual re trigger adjustment and only a brief mention that the trigger is " 2-stage, adjustable, set between 3.3lb - 4.4lb, adjustable for reach". My other AI AWs have ~ 2lb-12oz first stages with ~ 1lb second stages which is what I like, kind of similar to the Geissele two-stage triggers in my ARs. I had LabRadar issues too so it was a frustrating day in many ways.

I did shoot some good 5-shot groups and am confident that 38.0gr of Varget is the sweet spot in terms of accuracy, velocity and pressure so I'm going to try different primers and possibly play with seating depth. I need to confirm the best load using H4350 as well. I'll post some results soon.

Wow, that is a light second stage! I'm using a Timney Calvin Elite 2-stage trigger, and I believe it's currently set up for 2lb/3lb or 1lb/2lb, I can't remember. There is a definitive difference between the two stages which is really helpful. It was actually me shooting another shooters AI which made me like the 2-stage trigger.

Is the manual clear in telling you which screw to adjust or is it one of those "see a gunsmith" kinda descriptions? I wouldn't blame you putting this to one side for now, there's nothing worse than shooting for the sake of shooting if you're going to get frustrated. Still interested to see the results though, especially from good shooters!

 

[MCMXI]

Is the manual clear in telling you which screw to adjust or is it one of those "see a gunsmith" kinda descriptions? I wouldn't blame you putting this to one side for now, there's nothing worse than shooting for the sake of shooting if you're going to get frustrated. Still interested to see the results though, especially from good shooters!

The rifle manual says nothing about how to adjust the trigger, or whether each stage is individually adjustable. A Google search lead me to a PDF version of AI's trigger adjustment manual. For some reason, that instruction manual wasn't included with my rifle. It appears that the first stage is non-adjustable and is set at the factory, but the second stage can be adjusted. The manual is a bit vague in that it states "The trigger weight range of adjustment is 1.5Kg Min 2.0Kg Max; the trigger is factory set at 1.8Kg". So this equates to 3.30lb min, 4.40lb max with a factory setting of 3.96lb. I'm assuming that they mean the total trigger pull weight. Added in edit: Turns out that the first stage is adjustable (take up) and the second stage (break) is not. The second stage is 2 to 4oz at the moment so something is clearly wrong. Don't know if it's sear engagement or pull weight but trigger is going back to MHSA for evaluation (see below).

http://www.65guys.com/wp-content/uploads/2015/08/AI-15614-1-Trigger-Weight-Instructions.pdf

 

[edwardware]

I see that provocative "is NOT user adjustable" and I get all warm and fuzzy anticipating a good challenge.

 

[redneck2]

FWIW...I love these threads. Actually learn something, versus the “handgun for bears”, or .308 vs. 30-06

 

[MCMXI]

FWIW...I love these threads. Actually learn something, versus the “handgun for bears”, or .308 vs. 30-06

Me too! Looking at the schematic of the trigger above it's kind of obvious that what AI calls the first stage is what I would call the second stage. So there's no adjustment of the second stage (break), only the first stage (take up) .... well that sucks … for me since the second stage is the problem!! Also, I think the trigger as shown above is between first and second stages but I could be wrong about that. I spoke with MHSA later this afternoon and they asked me to remove the trigger and ship it to them for inspection. The upside is that I can pull the trigger off one of my other AIs and use it in the AX until a replacement trigger is sent out to me. MHSA will contact AI if necessary assuming they can't resolve the issue.

 

[MCMXI]

Still interested to see the results though

Here's my test from yesterday with 5-shot groups. I didn't get any heavy bolt lift, cratered primers or significant marks on the case head for any of these loads. Moving the bullet out .018" seemed to lower pressure enough. As I mentioned earlier, I really struggled with the trigger yesterday so hope to do better when I get the (or new) trigger back. The last two groups were shot as a 10-round group as far as the LabRadar was concerned and I can't explain the ES spread ... sorry.

 

[MCMXI]

The AXMC trigger is on its way to MHSA. The trigger shoe is shown backwards relative to the trigger housing. It's a heavy bugger for sure ... much heavier than any trigger control group I've ever handled which includes Kimber, Remington, Jewell, CG Extreme, TriggerTech, Timney and probably a few more that I can't remember.

 

[MCMXI]

This morning I removed one of the AW triggers, cleaned it and installed it in the AX. It works great with a 2lb-8oz first stage and a 1lb-0oz second stage so I'm fairly sure that something is wrong with the AX trigger that I shipped back to MHSA. I took some pictures of the sear to give a better idea of how the two-stage trigger works. It's an excellent design that gives more sear engagement when the rifle is cocked compared to a typical single stage trigger, which adds durability and safety, and less sear engagement for the second stage for a very clean and crisp break. I have two-stage triggers in various ARs (Geiselle and Jewell), a Lee-Enfield No 4 Mk 2, and all four AIs and it's my preference for any rifle trigger. TriggerTech is introducing a two-stage Remington 700 trigger in the near future.



Sear engagement when the cocking piece is in contact with the trigger bent (cocked)



Sear engagement when the trigger has been pulled through the first stage.

 

[Nature Boy]

Pretty cool

 

[WelshShooter]

Wow, just goes to show how little sear engagement there is on the second stage! Thanks for the cool pictures. Hopefully MHSA get it sorted for you.

 

[MCMXI]

Wow, just goes to show how little sear engagement there is on the second stage! Thanks for the cool pictures. Hopefully MHSA get it sorted for you.

The trigger is arriving at MHSA today and I have no worries at all about this. MHSA is a an excellent company who I've been dealing with for over 10 years. They'll either send me a new trigger or figure out what's wrong with this one and address the issue. The upside is that I've learned more than I would have. I find I don't learn much when things are going well.

Typical sear engagement for a single stage trigger is around .012" to .015" which has been proven to be stout enough to withstand most reasonable drop tests while allowing for a sufficiently clean break. I don't have access to an optical comparator but the sear engagement for the AI trigger shown appears to be around .020" for the first stage and .005" for the second stage, with a total pull weight of 3lb-8oz. I've had three AIs for about 9 years now and have never adjusted or messed with the triggers during that time. At the very least I plan on removing them all and cleaning them with Hornady One Shot and putting a drop of EWL on the sear. The trigger I removed from one of the AWMs was very oily.

 

[MCMXI]

No update on the AX trigger yet but the AW trigger that I temporarily installed works well. I've decided to stick with 38.0gr of Varget and the Berger 130gr VLD bullet with .005" jump to the lands. I shot a very rushed bullet seating test on Wednesday and repeated the test today (sort of) with decent results. I'm going to follow the advice of @Nature Boy and do a primer test next to see if it makes a difference. Here are the two bullet jump tests that I've done. The cold/clean bore test shows very little POI shift which is typical for quality barrels. I'll post the results of the primer test once I've completed it.

 

[WelshShooter]

Nice shooting! Your five thou group in the bottom picture shows same POI as your zero, has a tighter grouping and shows a lower extreme spread in velocity. Might be worth pursuing this and increase the sample size to see if its repeatable.

 

[MCMXI]

Here's the primer test from this morning with .005" jump for all loads. Next up will be some groups at 400 and 700 yards. @Nature Boy likes the CCI 450 and Fed GM205M results due to the lack of vertical stringing so I'll be testing those two loads again.

 

[Varminterror]

To properly zero the scope, you leave the windage and elevation turrets set to zero, simply loosen the three set screws on the turret and turn the screw to move the reticle to the desired position. With the screws backed off, you aren't turning the turrets, you're only moving the reticle. When you're done, you simply retighten the set screws. The nice part is that the machine screw has "infinite" resolution so you don't need to live with a zero that's some value above or below, left or right of the horizontal and vertical planes that you're trying to get on. With every other scope I've seen, reticle movement occurs in discrete clicks determined by the resolution of those clicks.

Revisiting this one tonight, and it occurred to me, although I had never tried it, or thought to do so, I bet the Bushnell DMRII and other Elite Tactical turrets could be used somewhat similarly. For the DMRII/ET line, reset is pretty standard, you match up POA/POI, remove the turret, and replace to show “0,0”. But now I’m wondering if a shooter were stuck between clicks, it might work you use a dummy screw with a small jam nut (or maybe the turret retaining screw even) to nudge the reticle that little bit such the turret engagement detents wouldn’t move while the reticle did slightly. I might have to tear the top off of one of mine tomorrow morning just to see where the detent teeth are mounted, and if this is possible.

 

[MCMXI]

I'd be interested to hear what you find. I've had the RAZOR GEN II HD for more than a few weeks now and I really like it. It's built like a tank but I have zero complaints other than the Vortex lens caps that I'll replace with ones from Tenebraex.

 

[WelshShooter]

Revisiting this one tonight, and it occurred to me, although I had never tried it, or thought to do so, I bet the Bushnell DMRII and other Elite Tactical turrets could be used somewhat similarly. For the DMRII/ET line, reset is pretty standard, you match up POA/POI, remove the turret, and replace to show “0,0”. But now I’m wondering if a shooter were stuck between clicks, it might work you use a dummy screw with a small jam nut (or maybe the turret retaining screw even) to nudge the reticle that little bit such the turret engagement detents wouldn’t move while the reticle did slightly. I might have to tear the top off of one of mine tomorrow morning just to see where the detent teeth are mounted, and if this is possible.

I'd be interested to know what you find out as I have a Bushnell Elite Tactical ERS on my 6.5x47 Lapua so it'd be handy to know for future.

 

[Walkalong]

Revisiting this one tonight, and it occurred to me, although I had never tried it, or thought to do so, I bet the Bushnell DMRII and other Elite Tactical turrets could be used somewhat similarly. For the DMRII/ET line, reset is pretty standard, you match up POA/POI, remove the turret, and replace to show “0,0”. But now I’m wondering if a shooter were stuck between clicks, it might work you use a dummy screw with a small jam nut (or maybe the turret retaining screw even) to nudge the reticle that little bit such the turret engagement detents wouldn’t move while the reticle did slightly. I might have to tear the top off of one of mine tomorrow morning just to see where the detent teeth are mounted, and if this is possible.

There you go, thinking again.

Must be feeling better.

 

[Varminterror]

There you go, thinking again.

Must be feeling better.

MUCH!

 

[MCMXI]

I shot the 10-shot group shown below at 300 yards this morning using the AXMC. I posted the results in a long-range load development thread started by @Nature Boy, but in order to keep this thread self-contained I'm posting it here as well. The Applied Ballistics app on my phone indicated that I needed to dial up 0.9 mil from my 100 yard zero for 300 yards but it looks like that was almost two clicks too much … something I need to look into. This seems to be a good load for this rifle and I'm fairly sure that the vertical error was in part due to my not controlling the rear of the rifle as well as I should have. I was shooting off a concrete bench using an Atlas bipod up front and a rubber pad at the rear. All rounds were fed from the magazine. I need to do some more work but overall this load seems to be close to what I want.

 

[WelshShooter]

Nice shooting! Did you consider humidity, air pressure and declination within the ballistic app? When I do long distance shooting the target at 1,000 yards is roughly 30 yards lower with respect to the shooters position and this in turn reduces the amount of elevation needed. Throughout the year, my elevation could vary between 8 mrad to 9 mrad using the same ammo depending on environmental conditions!

 

[MCMXI]

@WelshShooter, thanks for the feedback. I do enter the relevant variables in the app so at this point I'm not sure why there's a discrepancy. The 300 yard target at that range is elevated above the shooting position but not by more than a few degrees. I adjusted scope zero last night but only by a small amount (< 0.1 milrad) based on the primer test results. There are a number of things that could cause a .17 mil vertical error but I don't think it's an incorrect bullet velocity or BC input. The most convenient is to assume that the target was at 275 yards rather than 300 yards but that seems unlikely. That said, I'll confirm with a range finder next time I'm there. I'll shoot a known 400 yard and 700 yard target this weekend if I have time.

Note: Google maps indicates that the 300 yard target is 300 yards +/- 3 yards from the firing position.

 

[Nature Boy]

I'm fairly sure that the vertical error was in part due to my not controlling the rear of the rifle as well as I should have.

If you’re sure then I believe you. Does the buttstock on the AXMC have a bag rider?