Federal Syntech 150gr TSJ in Shadow 2 - POI shift?

[nasty618]

Hi gents

 

I am getting a 1.5-2 inch high and left POI shift with this ammo in my Shadow 2 at 15yds. In comparison, PPU Prvi 124gr is spot on.  Groups with 150gr TSJ are generally bigger but still acceptable for USPSA match ammo. 

 

I shoot two different games with this gun. I use PPU for Accuracy and Federal Syntech for USPSA... Winter accuracy is my primary game right now, so drifting sights is not an option at this time. I may do it closer to the spring/summer time when USPSA becomes the only game I shoot.

 

I was just wondering if anyone has experienced an issue with Syntech 150gr TSJ ammo where the POI changes when compared to their other/regular ammo?

 

Thanks in advance!

[CZ85Combat]

It is not uncommon for POI to shift from one brand of ammo to an other.

[Intel6]

Common and you are using two different bullet weights that cause shifts in POI.

[nasty618]

Makes sense... Thank you!!

[malobukov]

Is the shift vertical or horizontal? It is common for POI to be slightly higher with heavier bullets. Lower muzzle velocity means the bullet spends more time in the barrel, so muzzle can rise more.

 

[Hi-Power Jack]

33 minutes ago, malobukov said:

Is the shift vertical or horizontal? It is common for POI to be slightly higher with heavier bullets.  

 

I've seen POI shift both ways (vertically and horizontally) with different weight bullets    

[nasty618]

I'm my case the shift is in both directions - about 1 inch up and ~2 to the left @ 15 yds. 

 

If 124s are spot on, I guess trying out some 115gr bullets might be an interesting test.

 

 

Edited December 29, 2018 by nasty618

[malobukov]

39 minutes ago, nasty618 said:

If 124s are spot on, I guess trying out some 115gr bullets might be an interesting test.

I will venture a guess that 115 gr will be just like 124.

 

Horizontal shift is more interesting. I would try switching hands to ensure this is not related to asymmetric grip pressure.

[nasty618]

Good tip, thank you!  Although... wouldn't that become apparent with any ammo?  I do intentionally try to have a 60/40 weak/strong hand grip strength

Edited December 29, 2018 by nasty618

[malobukov]

41 minutes ago, nasty618 said:

Good tip, thank you!  Although... wouldn't that become apparent with any ammo?  I do intentionally try to have a 60/40 weak/strong hand grip strength

If your grip is neutral (symmetric left to right), then the muzzle would move only up and down during recoil. If your grip is weaker from one side, the muzzle will tend to also deflect towards the side where the grip is weaker. It's a bit more complex because the pressure is not applied exactly left to right or right to left, but the key is that lateral symmetry is no longer there.

 

In the extreme case, consider shooting with right hand only and weak grip. During the recoil, your muzzle will lift up and towards the left, because you have four fingers on the right and only one thumb on the left.

 

So every time you shoot the gun, its muzzle traces that slanted line. If you zeroed your gun with your grip for 124 bullets, a 115 grain bullet will leave the barrel sooner, and 150 grain bullet will leave the barrel later, so points of impact on the target will also be along that line. 150 grains will hit high left, and 115 will hit low right (the latter difference might be too small to be noticeable).

 

In reality this is a crude simplification, and you might observe other effects, too.

[nasty618]

Interesting! I'll do some more controlled groups WHO, SHO and vice grip it freestyle on a rest.  But it's good to know that it's probably not just me but also the physics and ballistics of different projectiles that would make this POI shift almost expected.  Thank you for that!

[Wrecks]

Different weight and velocity = different POI

[OnceACowboy]

Same thing happens in my Tactical Sport when I switch from 124 Berrys to the 150 Syntech, 2" left and 2" high. 

[Baron95]

On 12/29/2018 at 4:31 PM, malobukov said:

150 grains will hit high left, and 115 will hit low right (the latter difference might be too small to be noticeable).

 

 

I know this is an old thread, but I'm struggling with this issue - any suggestions on how to fix it?

 

I'm having problems with my new X5 Legion with big shifts even with 150gr Syntech (very weak) vs 147gr Freedom (mild) vs 147 gr Blazer full power - little high very left, dead-on, slightly low right, respectively. On my Glock 34 (even longer barrel) and all other handguns (shorter barrels) there is little to no difference. Yet on the Legion it is a big difference 3"left on Syntech 150gr.

 

Open to all suggestions on what to adjust. Is it likely to be more trigger or grip? On the Legion I can't run both my thumbs forward like I do on the Glock 34 as they bounce off the controls, so I have to run thumbs up at a 45 degree angle or so. Is the lack of thumb pressure the likely issue?

 

I love the recoil impulse on the Syntech 150gr but it shoots so far off from every other load - I'd like to bring it more in line and fix whatever issue I'm causing.

 

Thanks in advance for any suggestions.

Edited July 15, 2020 by Baron95

[rowdyb]

9 hours ago, Baron95 said:

for any suggestions.

1. Shoot only one brand/type of ammo. Not 2, 3 or 4. One. Then this variable doesn't get introduced. It is easier to chase down what you're doing if you keep ammo same same all the time.
2. You have adjustable sights, use them. Keep a notebook of the changes. For example set the sight all the way down and all the way to one side. Measure the clicks it takes from each to get to zero. So your notes would be like (Syn150gr X5 UP13 LFt18.  Frdm147gr X5 UP16 LFT16) or use the zero of one ammo and measure changes from it. (SYN150gr  UP4 LFT3) which just takes a little bit more attention if you're swapping back and forth. See bullet point 1.
3. Realize your job is to be a stable platform for the frame of the pistol and that your inputs should cause no movement in it. You can have amazing stance and grip but if you have crap sight alignment or crap trigger pull then who cares?
4. Have someone else who is better at group shooting than you shoot your gun for outside confirmation.

[WxGuy]

Yep, what Rowdy said!!!

 

[Baron95]

@Rowdyb and WxGuy

 

Thanks for the suggestions. What got me into this mess is that I switched from 3 Glocks (34, 19, 43) to 3 Sigs (X5Leg, 365XL, 365) for SSP/CCP/Bug right in the middle of this ammo shortage (I don't reload). On the 365XL, 365, 19 and 34 ammo changed cause no appreciable change in POI (up to 50 ft) other than the very slight up with the slower loads on the 34.

 

The X5 Legion was a different story - massive (+/-3" at 50 ft lateral) changes.

 

I did take good notes - I actually rip the ammo box lid and right the results and keep them for reference.

 

I went to the range today, and it appears grip pressure (from weak hand) and the long/mushy take up on the X5 trigger combined with the long barrel are causing it. Looks like I need to find a more consistent grip/trigger pull to be able to shoot the Syntech 150gr. It's driving me crazy as it is just with this gun.

 

Any other ideas welcome.

[hey.moe]

A year ago or more I noticed a similar shift from 124 gr Blazer Brass to Syntech 150 gr in both of my Shadow 2s. I confirmed it about six months later. But, now I'm starting to better appreciate the effect of grip and need to revisit the issue one more time (when ammo availability permits).

[Packageman]

Interesting data thanks for sharing