Light bullets + J-frame = shoots low?

D

dyl

New member
Folks, I've just started reloading and have come across a potential problem in Point of Impact. I'm trying to figure out if my low shots in my snub nose are because I'm shooting:
125 grain FMJ, 5.3 grains Unique, Winchester brass, Winchester small pistol primer, Overall length 1.47 inches.

The short thread is:
http://thefiringline.com/forums/showthread.php?t=484364

Out of a scandium snub nose, groups are tight but about 3.5 inches low at 5-7 yards.
Out of my 6 inch Model 27-2, elevation is spot on at 5-7 yards but a couple inches high at 25 yards. (strange yes?)

One possibility is I am not accustom to the XS front sight that came with the snub nose. I have been lining up the top of the XS dot with the top of the rear notch. If this is incorrect and I am supposed to see all of the dot like a shotgun bead, this accounts for about 1 inch at 5-7 yards. What about the rest of the elevation?

I have been given sage advice to the load settings the way they are and that it could be the shooter and the sights. It may be both, and my question is can the lightweight bullet be contributory to low elevation at 5-7 yards? About 2.5 inches worth? Any J-frame shooters shoot low with 125 grains?

If the bullet leaves the barrel "prematurely" I'd think I want to back off the powder charge (not so low as to squib), crimp more, and reduce overall length closer to minimum length in order keep the bullet in the barrel as long as possible within safe limits. - Good or bad idea? My thinking is that higher pressures would build from shorter overall length and more crimp but with a lower starting charge (I've tried 4.3 grains, no squibs) it would remain within safe limits. I would not be reducing below 1.44" which is minimum OAL.
 
Burying that big bead front sight in the notch seems like a waste. Get it up and free and see where you hit. These little guns seem very sensitive to the way they are held and shot. I would stick with one load to eliminate that variable. Shoot, shoot, shoot.
 
Unless you plan to use the J frame as a dedicated target revolver, you are over thinking the situation.
A J frame is designed to be a close range, personal defense weapon. I carried one for many years, as my primary duty gun, and I can offer the following info, based on years of experience.
Over the course of time, we were issued various loads to be carried as duty ammo. From 158 gr., down to 110 gr. We had no control over the loads, and had to use what we got.
Therefore, keping in mind the designed purpose of the gun, you have to learn where the gun shoots with the ammo you are using. If you are hitting 2 inches high, aim two inches low. At self defense ranges, 2" makes no difference. As long as you can put the slug COM, you are getting all you can get from the gun, cartridge combination.
I wouldn't worry about a couple of inches in elevation for another reason. In a high stress situation, with someone attempting to kill you, you will be so hyped up on adrenalin that it will be all you can do to hit anywhere on the BG.
Nuff said
Good luck
 
"Light bullets + J-frame = shoots low"

Makes sense to me. Most guns do that with light bullets since the bullets are moving faster. I shoot primarily 148 gr. wadcutters and 158 gr. bullets in both of my J frames. And a little .357 in the 649.

I shoot them at 50 and 100 yards sometimes if there's a target down range that's large enough for me to hit. One range my father and I used to belong to near Lexington VA had a steel plate hanging at 100 yards and that was a blast for handgun shooting.

I don't think I've shot at less than 15 yards since the first day I shot my P-32 10 years ago.
 
Deja Vu - you shoot high? Are you using 158 grain bullets? Are these standard notch + post/ramp sights?

Yankee - When you say it like that it would be pretty funny to declare the snub nose as my race gun. Maybe I should get an extended cylinder release button ;) I do prefer that impact is point of aim so that I know that when I do better it shows. It gives me a goal to work towards. And I'd like to push the limits of my ability with it - I figure if I'm good with a snub nose, I'll be better with just about any other trigger. I'm actually going to try resist kentucky elevation :) since after these bullets run out I'm going to find something heavier. But 800 shots could take a while. It's good to remember COM is what counts. Thanks for the reality check regarding Self D.

5thShock - Yeah i have to go back to my original specs. I already started another batch with reduced charge and lower overall length to solve the "problem". I'll finish a box of those and go back to the original specs (although I still have a box for testing). The strange thing about this XS dot setup is that the rear notch is cut differently - deeper than on a standard airweight. I thought: why would they do that unless I'm supposed to use the deep trough? - but apparently with 125 grain I'm supposed to see some ramp. I might start another thread to see if anyone with a M&P340 has had decent POA/POI.

Johnbt - The good news is that for some reason they shoot with the correct elevation out of a 6 inch revolver at close range. And they go bang at least. But yes, I'd like to get good with this little snub nose and consider that an ultimate challenge. These big dot sights might make it even harder. Whoops I meant fun.
 
I tend to agree with Yankee. The big dot is not meant for precision shooting. Find a load you like, then learn to adjust your point of aim or sight picture accordingly.
 
J frames tend to be regulated from the factory for the 158gr standard pressure load. Lighter weight/faster bullets will shoot low.
 
It's common for those guns to shoot low with light bullets. I've read on the vast area of nothingness known as Al Gore's internet that the heavier, slower bullets push the gun up more upon recoil, thus making them shoot higher than the lighter bullets. Personally, I've found enough variation between snubbies to make me think that it depends on the gun. I really think my 637 power port is regulated for lighter bullets. That's just supposition, though, as most of what I shoot is hand-loaded. I fling a lot of cast bullets down range due to price and the characteristics of penetration and wound channels with SWCs. I'm not just carrying that thing for people, but stray dogs and maybe coyotes who are a little too curious. Anyway, enough rambling. Get some 158 grain cast bullets and fling those out of that little j-frame, and it should raise the POI.
 
DYL:

A bullet is moving during recoil. The faster the bullet is moving the lower it strikes the target. Try some 158 grain bullets and see what happens. On a sighted in pistol or revolver the barrel points lower than the sights to allow for vertical recoil and bullet lag while the bullet is in the bore.

Semper Fi.

Gunnery sergeant
Clifford L. Hughes
USMC Retired
 
I've only been reloading for about 18 months, so here's my advice for what it's worth.
I wouldn't mess with the OAL. If you're happy with your grouping and they're consistant then you're doing everything right. The issue is velocity. If you lower the charge but seat the bullet further into the case you may end maintaining the same pressure, or possibly even increase it a little which will increase the velocity and your POI would remain the same.
With one of my fixed sights guns I was getting low POI's. My groupings were good, just low. What I did was load up some rounds with a series of lower charges: 5.6, 5.4, 5.2, etc all the same OAL and color coded each primer with a Sharpie so I knew what charge was in each round. Then I just shot using a rest until I got the POI to match the sights at the distance I wanted.
Out of my 6 inch Model 27-2, elevation is spot on at 5-7 yards but a couple inches high at 25 yards. (strange yes?)
Click to expand...
Not really, the bullet is arcing upward as it travels. A higher velocity should give you a flatter arc.

I could be completely wrong with what I've posted, my 18 months of experience vs. decades of some other folks here, but this was how I solved a similar problem. Best of luck, dyl.
 
Folks, I've just started reloading and have come across a potential problem in Point of Impact. I'm trying to figure out if my low shots in my snub nose are because I'm shooting:
125 grain FMJ, 5.3 grains Unique, Winchester brass, Winchester small pistol primer, Overall length 1.47 inches.
Click to expand...

It's counter-intuitive that a light bullet, presumably being pushed faster for a given charge, would shoot low. Nevertheless, that seems to be the case. Commercial 125gr JHP shoots low in my snub, handloaded 158gr LSWC shoots to point of aim.

Try the "FBI load" (158 grain LSWC, 3.7gr Bullseye), and see if it doesn't shoot to point of aim.
 
It is to be expected for lighter bullets to shoot lower because lighter bullets are not in the barrel as long as heavier bullets are. The heavier bullet will be in the barrel for a longer duration of time which allows time for the gun to rise in recoil and consequently print higher.

Use a heavier bullet or aim higher.
 
Shooting a M&P 340 or 360?

I have a pair of M&P 340's with the standard XS front sight.

I typically shoot 130gr & 135gr loads out of them. The 130gr loads have been both standard pressure FMJ budget loads as well as the Winchester RA38B (PDX1) +P.

I can achieve ragged hole groups at reasonable defensive drill distances using aimed fire with assorted middle weight (125-135gr) loads in my M&P's. (The heavier 158gr loads seem to do well, too, though.)

Have you read the sight company's info about using the Big Dot/XS front sight? At relatively close distances (think <15 yds) the POI is expected to be hitting the target under the center of the XS front sight (in the middle of the sight's coverage). That may take some time and practice in order for you to become adjusted to it.

If you're trying to use a typical sight picture/alignment that means you're expecting the POI to be at the top of the dot (when nestled within the U-notch), and that would make it seem as though you're shooting low.

When you move out to longer distances, though, you use the top of the dot as the POA/POI, more like you're probably familiar with when using traditional handgun sights and acquiring a sight picture/alignment.

I had an advantage when I got my first M&P 340, because I'd been using a set of the early Ashley Express Big Dot sights on one of my small .45's, so I'd already become accustomed to the POA/POI when using that system. (I also liked the big U-shaped notch of the snub's sight setup over the standard express notch with a vertical white stripe.)

If you open the .pdf catalog on their website ... http://www.xssights.com/index.php ... and look at Page 14, it'll give you a good picture of how the sights should be used at 15 yds & under, and then at 25 yds & farther out.

I've come to really prefer the XS sights on my M&P's compared to the older narrow & newer wide front ramps on my several other J's, even though I've painted the front ramps in both bright orange or white on the other snubs. I can simply pickup and use the XS sights on the M&P's to get faster, more tightly focused groups ... more easily ... than I can with my standard sight J's. My late-50's eyes really benefit from the XS sights.

Sure, you're going to experience the usual slightly lower POI when you start using 110-125gr loads in .38 & .357 revolvers, especially out at distance, but it helps to understand the intended application of the XS sights. I can consistently ring steel plate targets out at 50 yds using 130gr +P loads and one of my M&P 340's.
 
"One possibility is I am not accustom to the XS front sight that came with the snub nose. I have been lining up the top of the XS dot with the top of the rear notch. If this is incorrect and I am supposed to see all of the dot like a shotgun bead, this accounts for about 1 inch at 5-7 yards. What about the rest of the elevation?"

Wrong !!! The XS Big Dot is meant to primarily be a close range sight.

Cover your aiming point with the DOT .

It will look like this __O__

;)
 
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