Hello /k/,I have a Rock-Ola M1 Carbine with a type II rear sight. I have it set to it's lowest setting at 100 yards but the impacts are well higher than my point of aim. pic related. Please ignore the group size. I was in a rush to leave because I was shooting alone until someone else showed up and my mags are too spicy for this state.I suspect that the front sight was filed down too far by a previous owner but I wanted to see if anyone has some insight on something like this. I also want to know what the point of impact is supposed to be for 25 and 50 yards if the sight is set to 100. I apologize if this is too gun related for this board.
>>65324954Buy an ar
>>65324954I heard the m1 carbine is dogshit past 100 yards
>>65324954Here is a link to the technical manuals. Good luck OP.https://www.govinfo.gov/content/pkg/GOVPUB-W-a4a6ec2326a3857023aa7088b81ed1c4/pdf/GOVPUB-W-a4a6ec2326a3857023aa7088b81ed1c4.pdf
>>65324954it could be someone fucked with the sights but it could easily be the ammo. it was zeroed for some other gr weight or velocity and what your using now is different.it could also be you misunderstanding the sight picture. im not saying rifles with peeps have 6oclock holds its just an example. it could be you.
>>65324954>Rock-Ola M1 Carbinei hate you so much you glorious lucky faggot thats fucking awesome mother fucker
>>65324954Did you rest the rifle exactly the same way for all distances ? On rifles where the barrel is not free floating, differences in weight application can interfere with barrel harmonics and cause POI to shift.Also, combat rifles are usually zeroed using a "battle zero" setting which is equivalent to roughly 300-400m. That means the POI is almost always higher than the POA. This is for two reasons : 1) it allows better target visibility when looking through iron sights and 2) it eliminates the need to fiddle with the sight settings when target distance is unknown. You just aim for the waist or belly and you're basically guaranteed to hit somewhere in the torso area at any distance below 400m. Of course this is not ideal for civilian target shooting.I'd say this is the case with your rifle : based on the POI/POA difference at 100m your rifle seems to be using a battle zero.
>>65325113It shows it's age to put mildly. Without me holding the sling tight the barrel band will walk forward and the hand guard will fly off during shooting.>>65325102I hadn't considered bullet weight, admittedly. I can't imagine there is that much difference considering how few guns use .30 Carbine. I was using sight image 2.>>65325134I rested it the same and held a center zero during shooting. I wouldn't be surprised if the problems I mentioned above would throw my shots off some but even when the groups open up there is still a clear trend of the impacts going high as the distance increases.I have read that the front sights would get filed down at the factory or the first receiving unit during initial zero and I was thinking that could explain climb.
>>65325316>I can't imagine there is that much difference considering how few guns use .30 Carbineyouve never heard about modern new production ammo being overloaded compared to the orginal so decade or century old guns dont blow up?its pretty much universal for oddball calibers.
>>65325353whoops was supposed to say underloaded
>>65325316Your results are fairly consistent with what I said. Your rifle is probably using a 300 to 400m battle zero. The rise between 50 and 100m is normal in this configuration.There are actually two points where your line of sight intersects with the bullet's path. See picrel for the difference between a combat zero and "normal" zero.At 0m POI is lower than POA because the sight is sitting above the bore.At somewhere between 10 to 50m POI and POA coincide for the first time because your bullet path can be considered flat at this range and your sight line is tilted downwards. That's your "near zero" distance which from your results seems to be around 10-15m.Then the POI rises up until a certain distance and drops down to coincide with POA again somewhere around 300-400m, that's your battle zero.Rifle is fine. The M1 was never made to shoot paper targets with great accuracy anyways. It was made to hit man-sized targets up to a few hundred meters and it's setup exactly for that.
>>65325393Thanks for going into detail.I understand battlefield zero but what confuses me in this instance is that the rear sight is set to 100 yards but that doesn't seem to correspond to anything.
>>65325316>Without me holding the sling tight the barrel band will walk forward and the hand guard will fly off during shooting.You don't think this might affect accuracy?
>>65325451Of course it will. It partly explains why the groups are opening up, but I won't deny that my shooting was a big part of it.There is still a consistent movement of the grouping going upward as the distance increases and it doesn't correspond with the markings on the rear sight. That's what I'm curious about.
>>65325424As previous anon said it may be due to ammo. Different ammo load and weight can cause quite significant POI shift. Try using different ammunition. In your case since the trajectory seems to be flatter than intended I'd start either by using a weaker load or heavier bullets.If the discrepancy between the iron sight setting and the actual zero distance is bothering you, you can always take it to a gunsmith to get it fixed. But keep in mind that achieving a true 100yds zero will probably mean the other settings will be off without the proper ammo.
>>65325710I have ammo from Aguila and MAGTECH. Both are 110 grain and if wikipedia is to be trusted then authentic .30 Carbine ball ammo is also 110 grain.I suppose I am getting too autistic about it since these carbines weren't made with any real precision in mind. Is the 300 yard max adjustment on the type 2 sight just wishful thinking on behalf of the designers?
>>65325760US military ammo for the M1 Carbine was 110gr bullet traveling at about 1900fps, which almost every modern manufactured 110gr ammo replicates, so unless you somehow got a batch of bad ammo from both it's not the ammo. The 300 yard is very wishful thinking, 200 yards is usually the max practical range for hitting a decently sized (e.g. man-sized) target reliably. I'm wondering if the barrel band not being tight causing the handguard to return to its home planet may be causing some severe vertical stringing. See if you can punch out the barrel band spring to see if it's not actually broken. You might need to use channellocks to gently squeeze the barrel band to increase tension. easier route would be to buy a new one. The other option is indeed the front sight is fucked and buy a new one and gently file it while at the range. Look up ballistics calculators to see what drops are supposed to be if the sights are set for actual ranges they're supposed to be at. Numrich is your friend for parts https://www.gunpartscorp.com/gun-manufacturer/us-military/rifles/m1-carbine/parts-list
