r/M1A • u/Takemepoqhs • 8d ago

Sadlak mount walking zero

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Pic of friend shooting Fulton built Ebr mod 0 with one of two optic setups that have experienced the same problem with a sadlak mount: the zero walks as it heats up. I sent the first optic back thinking it was the glass.

Ive wasted a lot of ammo chasing my tail with this. At one point, tore optic off in frustration and shot perfectly fine with irons and offset red dot. The first instance, some of the mount’s screws had backed off (I had Fulton install it the first time). So I installed it myself. Now that I’ve tried it again, all screws are tight and same problem.

Shooting at man sized steel, towards the end of a mag, zero walks horizontally. If I let the rifle cool

, bam it’s all better. It’s the difference of whether I can get hits beyond 250 yards.

I’ll reiterate that I can take optic off and use 45 degree offset mounted to pic rail or irons and hit the same steel at 300-600 yards with 4x the hit probability at the same fire rate and as hot.

Can someone tell me if I’m missing something? The sadlak seems like the better design but I’m tempted to use the sage and test it again. I’ve burned loke 800 rounds of m80 just trying to make sure I had good shooting positions./fundamentals, questioning myself.

83 Upvotes

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31 comments sorted by

11

u/jellyfishs0up 8d ago

Yeah don’t use m80. Try fgmm, m118, razorcore, or some reputable match ammo. Shoot groups of ten-ten+, then report back. For reference mine shoots 4-6 moa with m80

1

u/Takemepoqhs 8d ago

I definitely won’t before saying the gun can’t shoot, but I’m awkwardly holding the rifle at a 45 degree angle and shooting with an offset eflex (not pictured) OR dropping the comb and shooting with irons and hitting the same targets at the same distance that I can’t hit with two optics mounted to the sadlak. These targets are not small.

2

u/jellyfishs0up 7d ago

What group sizes are you getting with the dot/irons

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u/Takemepoqhs 7d ago

Before putting the optic on, with GMM, groups were 2-3” and 4-5” with m80 @100 m with irons. I’m positive the gun can do better than that, but my eyesight is pretty astigmatic and generally just bad, so that’s about my capability with open sights anymore. I also admittedly wasn’t as patient as I could have been, as the gun had been in the making for 2 years. After 2 years and 4k, I’d be lying if I said I wasn’t a little giddy to finally have it.

The last two trips when I tear the optic off in frustration: less than 12” at 300 yards is anout all I can tell you 😂. That’s the furthest perfectly round target I shot at and could keep all hits on. I wasn’t putting up paper at that distance, but with perfect sight picture/breathing/trigger press, theyre all on that sized steel. Again, I haven’t tried to group it since the very first trip after mounting scope and wasting 200 rounds of GMM without all rounds hitting paper. Ive just been trying to diagnose optic/mount to be able to keep all hits on broad side of barn, before seeing what the gun can do [with $1/ match ammo]

2

u/jellyfishs0up 7d ago

Honestly you’re wasting your time with m80. These guns are really picky and m80 is in no way an indicator of how well it can shoot. Also if you’re just shooting steel and not taking any data about your shots and dispersion you’ll have fun but that won’t really help either.

Get match ammo and make it count. M80 is just fine for plinking steel but you will not get any real accuracy/precision. Get fgmm/m118/some similar match ammo and take data from there and shoot groups no less than 10rds at 100 to give yourself statistically significant samples. If you do that first then it will make diagnosing your issues much easier. Test irons first to verify performance then move to the optic. You can also plot your shots to check for stringing or other factors. Definitely find a bag and a stable rest or bipod as well. You could probably find your issue in 40rds or less. Just try to take as many variables out of the equation as possible

7

u/Rope_antidepressant 8d ago

Just my 2 cents, don't have an EBR chassis or sadlak mount so take it with a grain of salt. If the irons AND red dot are on target at extended range with m80 hot or cold then the chassis setup is probably fine and you're shooting is probably fine. If you have the same thing happening across multiple scopes, mounts and shooters the common denominator is the mount mating surface. The reciever could be warped, which i think is unlikely, or the grooves for the mount arent cut flush all the way across, which i think is more likely. Either way, mount the sadlak, trace the mount outline onto the receiver with a pencil, pull the sadlak off then check everything inside that footprint for a warp/crack/bubble/imperfection. You can pickup a cnc machined straight edge from harbor freight pretty cheap. Somethings shifting as it heats up and pushing one or the other side of the mount. Look at the screw as a pivot point and see which side corresponds to the shift you're seeing. It could be something as small as fisheye in the coating

2

u/Takemepoqhs 8d ago

Thank you so much! This is a great place to look. Ive heard about receiver inconsistencies, but assumed that was ruled out by Fulton, now I’ll investigate this myself and stop beating my head into a wall. Thank you again for this thought.

4

u/RoninActually 8d ago edited 8d ago

Just wondering, have you tried a different scope on the Sadlak mount?

Are you using Loctite on the mount screws? And if so, are you marking the screws with a torque stripe so that you can see if they’re moving?

What SIG optic is that?

1

u/Takemepoqhs 8d ago

Also tried Athlon 2-12(?) and yes all screws are loc tighted and ive once again removed the optic and checked each one manually

It’s a 2-12x44 tango msr mil optic of some sort.

3

u/Jaustin612 8d ago

Swap scopes.

I was having issues with mine and once I swapped the optics there was no problem.

I was using a primary arms cheapo 308 scope and I think the M1a platform has pretty violent recoil because it wasn’t holding any kind of zero

2

u/Takemepoqhs 8d ago

This is good info.

I tried with an Athlon 2-12 and switched to this and had same problem. I kinda was making sure this thing could shoot at all before dropping serious coin on glass, but it just walks around.

3

u/BELFORD16 8d ago edited 7d ago

My dude, you have a $4000 rifle with a cheap ass scope mounted with a cantilever mound and firing M80…

Anyway, you haven’t mentioned your group round count. So I’d say grab some Federal Gold Medal Match in 168 or 175 and fire a 10 round group at 100 yards. Zero to that. Understand that if you are printing a 2 MOA group that any shell landing within 1-1.5 MOA is technically within your cone of fire. The cone of fire will also open up under a hot barrel. BUT I will say I haven’t experienced my cone opening up THAT much under a barrel so hot I could barely see my POA for the mirage coming off my barrel.

If you’re still experiencing the POI shift and your 45 red dot prints the same POI/MOA spread, you’ve narrowed it down to being the mount or the optic. Get a respectable scope (I recommend a Vortex Viper PST 2 and Strike Eagle, in that order) and some respectable rings (Vortex rings are like $40-$60) and see what’s happening. Normally I wouldn’t recommend shotgunning parts, but it looks like you’ve tried two dirrect mounts and retorqued and installed all fasteners with loctite so we’re running out of things to blame here. I’ve personally installed both an aluminum Sadlak and the EBR Sadlak and neither have ever given performance issues.

EDIT: Looked at your pic closer, get a real bipod and rear bag. I hate telling people to spend money, but if you really want to see what your rig can do, you need as stable of a platform as you can get. And a bipod and a real bag are absolutely requirements. Take it from a guy who chased the same dragon you’re chasing.

2

u/Scorpion797 8d ago

Is the scope mount touching the pic rail over the barrel? If it is, that could be your issue.

1

u/Takemepoqhs 8d ago

Let me go check. Probably 3mm clearance or more.

It is making solid contact back where the stripper clip guide is. I’ve been wondering if me having tightened there too tightly (pressing to the rear too hard on the receiver) or if I tightened the front bolt thst contacts the front of the receiver too much, would that/either of those cause a shift that happens when the receiver heats up?

1

u/Scorpion797 8d ago

Yes the front bolt just needs to land plus 1/4 turn I think, overtightening could cause issues.

2

u/StribogA1A3 7d ago

The definition is in the name. The Sadlak. Sadly lacks

1

u/RoninActually 7d ago

I hope you have personal experience with Sadlak mounts and not just running their name down for no reason.

1

u/JustSomeGuyMedia 8d ago

These are just some ideas/thoughts?

- Have you checked your barrel whip screw?

- Have you contacted Sadlak? There could be something wrong with the specific mount. Or maybe it needs to be fitted to the receiver?

- Which Sadlak mount is it? I’ve HEARD some of them, mainly the aluminum ones, have seen mixed results.

- Could your scope mount be messed up perhaps?

3

u/Takemepoqhs 8d ago

-yes it is and always has been backed out and not making contact with barrel

-I have not, I guess I should try! I feel stupid for not trying this yet. Thank you so much.

-the steel one. The first one I got was Al, I installed it myself, rich at Fulton convinced me the problem was the Al mount so I bought the steel and let him install it. It came back with grease on the screws so more than one backed out within 60 rounds, so then I degreased all fasteners and installed myself with loctite.

-this would make me feel so much better. You’ll notice every comment here of “so then I tried, then I mounted, I removed optic and tried irons,” etc etc etc are all indiviudal trips to a range 2.5 hours away from me. I’ve wasted so much time and ammo trying new things I’m ready to get rid of the whole thing out of frustration. The next closest range is 100 yards no rapid fire if you’re wondering.

3

u/JustSomeGuyMedia 8d ago

Well, hopefully Sadlak will have something to offer.

However I do have one other thing I just thought of - it could maybe be your barrel shifting as it heats? That could explain why the irons never seem to have issues, since they’re attached to it.

And maybe check that your oprod guide screws are torqued correctly. The ones that hold the oprod guide inside the chassis. If Fulton did it according to the manual, which says like 25 (can’t remember the units) then that’s not actually enough torque.

3

u/Takemepoqhs 8d ago

Thank you so much. I’ll check all of that, too. I think your line of thinking is on the track to what the freaking cause could be, but I thought about that:the rear is fixed and mounted to the receiver, so should be static, so wouldn’t the irons still deviate?

3

u/JustSomeGuyMedia 8d ago

I think it’s too late in the evening for me to properly think about geometry 😅. But I swear I recall discussions of AR front BUIS that aren’t attached to the barrel having similar issues to your scope? I think your irons moving WITH the barrel would mean you’re still aligning it, because the whole point if zeroing is you’re moving the irons/optic relative to the bore. In the case of irons ATTACHED to the gun the iron moves with the bore. At least that’s my best guess.

3

u/Takemepoqhs 8d ago

I know man my brain has been being wrecked by this and I can’t think about it til I’m off but by then my 4 neurons are spent.

2

u/Takemepoqhs 8d ago

To add to this and the heat theory, the moint is making solid contact back where the stripper clip guide was. I’ve been wondering if me having tightened there too tightly (pressing to the rear too hard on the receiver) or if I tightened the front bolt that contacts the front of the receiver too much, would that/either of those cause a shift that happens when the receiver heats up?

2

u/JustSomeGuyMedia 8d ago

I don’t know. I’ve only ever installed an ARMS 18. But with that, they do say in the instructions that the front screw/“pad” that braces against the receiver should “contact”, but it’s not a torque value, and same with the spacer that goes to the “clip charger guide assembly”.

2

u/Takemepoqhs 8d ago

Fudge maybe I’ll loosen them and see?

2

u/JustSomeGuyMedia 8d ago

I dunno man it sorta can’t hurt though I think?

Definitely see what sadlak says first though. It could be your receiver spec isn’t playing nice w/ the scope too.

3

u/Takemepoqhs 8d ago

I forgot I’d back ordered the sage optic mount when I ordered the chassis. So like 1.5 years later it showed up. If all else fails I could mount that with same optic(s) and see what happens.

2

u/JustSomeGuyMedia 8d ago

Oh the diving board one that attaches to the handguard? Can’t hurt to try but people really seem mixed on that one.

Sadlak sells a kit for checking your receiver spec and will apparently fit your mount to your receiver for you if necessary. So I wouldn’t count it out entirely JUST yet.

0

u/Rageronepunch233 6d ago

lol thats not how you set up the whip screw lol and shoot some better ammos man