Anyone solve the first shot low and left phenomenon?

[GKC]

Try loading one round less in the mag and see if you still get the first round flyer. I have an idea but I don't want to risk a placebo effect.

OK, I might as well ask a dumb question, instead of just wondering about it...

What effect would one less round in the magazine have on the first shot?

 

[jpendergrass1]

OK, I might as well ask a dumb question, instead of just wondering about it...

What effect would one less round in the magazine have on the first shot?

I'm guessing here:

Maybe when the spring of a magazine is pressed to its full extent (full mag) then it wants to release that energy more to give it relief and go back to its natural state (empty mag). With a full magazine, that spring is pushing up on the next round with much more force than it would be with 1 less round. Just like how it is easier to load the first rounds into a magazine than it is to load the last couple rounds. When it pushes with more force, it could cause the round to be loaded faster and, possibly, not set completely flat and snug. Then the gun also has that spring pushing the next round up at a high force as well to affect it also.

Honestly, like I said, I'm guessing here but you have got to take all things into consideration. I mean, a 5mph crosswind can cause changes in bullet travel and the force of that spring in a magazine is definitely higher than the force of a crosswind.

Just wait, the guy is going to come back and have some really simple answer and it is going to turn out that I am looking way to in to this because of my engineering background.

 

[snubbyfan]

Aim high and right...

Seriously, as others have said, it's the pull you are making. There's a chart that has been posted on the forum here that breaks it down by where the shot is hitting the target, as to the likely cause (grip, trigger pull, etc.) If I can find it again, I'll post it here.

Found it for ya.

 

[Darryle]

I'm guessing here:

Maybe when the spring of a magazine is pressed to its full extent (full mag) then it wants to release that energy more to give it relief and go back to its natural state (empty mag). With a full magazine, that spring is pushing up on the next round with much more force than it would be with 1 less round. Just like how it is easier to load the first rounds into a magazine than it is to load the last couple rounds. When it pushes with more force, it could cause the round to be loaded faster and, possibly, not set completely flat and snug. Then the gun also has that spring pushing the next round up at a high force as well to affect it also.

Honestly, like I said, I'm guessing here but you have got to take all things into consideration. I mean, a 5mph crosswind can cause changes in bullet travel and the force of that spring in a magazine is definitely higher than the force of a crosswind.

Just wait, the guy is going to come back and have some really simple answer and it is going to turn out that I am looking way to in to this because of my engineering background.

This was eliminated via loading the first round directly into the chamber then inserting the magazine.

I think it is tension of the full magazine on the bottom of the slide, pushing the rear slightly and therefore bringing the front down. The only thing I can't explain is why the sights moving the same way wouldn't correct it.

I maybe wrong, but I haven't had time to make it to the farm to test several different scenarios.

I'd like to meet the guy who designed the frost free outside faucet and kick him in the taint.

Sent from my Tesla coil

 

[Darryle]

Okay, here are the results of the first magazine. Other than the 180gr Winchester flat nose FMJ shooting low vs the 165gr, here are the results. I loaded the first round directly into the chamber and shot it without the magazine in place. Then let the slide strip the second round and shot the remaining 14rds.

Sent from my ADR6425LVW using Tapatalk 4 Beta

 

[a62rambler]

OK, I might as well ask a dumb question, instead of just wondering about it...

What effect would one less round in the magazine have on the first shot?

Not a dumb question at all. It could have several possible effects. I'll give some later. My idea was to first eliminate possible variables. Posters were suggesting shooter error but due to his nice groups I doubted that and was trying to eliminate other things I've seen.

Reasons a tight mag spring could cause this. Additional pressure on the rear of the slide might change the pressure on the front part of the polymer frame just enough to change how it flexes. That's just a wild guess. I know the Sigma mags have a history of being really hard to get the last round in and wanted to eliminate that variable before diagnosing the problem. I can think of several other causes. It could change the drag on the slide and the slide to frame fit or it might lift the slide enough to change the fit of the barrel lug to frame. It could cause the barrel to angle down in the front of the slide. The cause will probable remain a mystery without high speed camera work to see what was happening.

One poster said it happened to him but only on the first shot. That could be simply a cold bore flyer. That's usually only seen on rifles because most don't shoot a handgun accurately enough to see it or they shoot at shorter ranges but it is still a factor. In O'cowboy's case it was a problem with a every full mag so the first thing to look at is if the full mag is the cause. If the problem is with a full mag only then see if one round less fixes the problem. If it doesn't then look to other factors. I've seen this problem in the past and sometimes one round less fixed the problem. Not sure why it fixed it in the other cases but it solved the problem.

 

[a62rambler]

I'm guessing here:

Just wait, the guy is going to come back and have some really simple answer and it is going to turn out that I am looking way to in to this because of my engineering background.

Just noticed this response and had to laugh. I don't have an engineering background so I don't know the excuse to use in my case. I guess it's just my background in solving crimes that makes me look at eliminating things or people before looking at the motive or cause. jpendergrass is as good an explanation as any I can also guess at. And since he has an engineering background his guess probably is better than my guesses.

If one round less fixes the problem then decide if you want one more round or better first round hit potential!

 

[a62rambler]

I ruled out shooter error because it happens Once per 15 round mag and always on the first shot. That's mechanical. Shooter error would be once sometimes, twice sometimes, four sometimes, three sometimes etc... I'll post my groups and you can see shooter error in action. LOL O'cowboy was having a consistent repeatable problem and that screams mechanical issue to me.

 

[Sebring Pop]

Snubbyfan has the answer. That chart knows more than I do.

 

[Darryle]

It was definitely the pressure from a fully loaded magazines. I shot 10rds by dropping the round directly into the chamber and with no magazine and each one printed withing the same group as the remaining 14rds. I then tried 14rds, 10rds, 5rds in the magazine and load, drop the slide and run and in each instance I got a nice group at 20yds. I appreciate the tips and the very sound thinking on the reason behind it. I think this little pistol is a keeper. I cleaned up the sear block housing, removing the "flashing/parting line" on the underside where it mates with the sear, dropped another 1/4lb off of the trigger and now it is perfectly smooth.

I ran 300rds of the 180 FMJ and 250rds of the Winchester Jacketed Hollow Points thru it today and not one single malfunction. I have close to 1000rds total and it hasn't hiccuped once, even after he trigger mods.

I ordered a set of Trijicon NS from Trijicon, 8 week lead time, we'll see. I could order the Meprolight for about $70 less, but honestly, did not know how long these have been on the shelf at Midway.

 

[Road Rat]

Just for giggles: Have you tried running a dry patch through the barrel before shooting?

Just in case there is still oil or cleaning fluid in the barrel!!

Hey, I'm grasping at details at this time.

 

[GKC]

If one round less fixes the problem then decide if you want one more round or better first round hit potential!

I routinely load my 16 round magazines with 15 rounds anyway, rather than 16...Net result is 14+1 in the gun, plus two back-up loaded mags in a carrier with 15 rounds in each. I guess if I get into a situation where 45 rounds won't take care of it, then I am in more trouble than I can handle anyway. Two or three more rounds will very likely not matter!

 

[Jeffersonwasright]

This was eliminated via loading the first round directly into the chamber then inserting the magazine.

My SD9VE doesn't allow loading a round manually. The round won't seat in the chamber unless it is actually loaded in from the mag.