Sevigny Competition Sight Heights POA/POI

[ErnieB]

I installed a set of Sevigny Competition sights on my G34 last year and only recently started shooting it regularly. The set I purchased had the recommended sight heights for the G34, standard Sevigny rear with a fiber optic front sight size: .115 wide .215 height. While shooting groups at 25 yards on an IDPA target cutting the center of the A zone in half with the sight picture I consistently shot groups roughly 4.5-5" high with 147gr Federal American Eagle. I shot several mags offhand and benching the gun and got the same results. While recently on a trip to Vegas, I stopped by a local shop and picked up a Sevigny front sight with a height of .245. Heading back the range this seemed to be too far in the other direction. I am now faced with having to file the taller front sight and experiment with getting the height correct. I don't remember having this issue with the Sevigny's on my other guns (G17 and another G34). Anyone else experiencing this? Would the 147 gr ammo cause that much of a difference in impact height at that distance vs 115gr or 124gr? I wouldn't think so but just thought I would see if this might be an issue with a recent run of sights.

Things I am considering:

- Filing the sight to achieve the correct impact

- Trying a set of Dawson adjustable sights

- Trying a set of Trijicon HD's

[jetfire]

With my G34, 115s shoot point of aim/point of impact with the .245 sight.

[Mitchell, Esq.]

- Trying a set of Trijicon HD's

Come to the Orange side...

[ErnieB]

I want to try a set of orange HD's but no one seems to have them in stock at the moment.

My stock G17 shoot POA/POI with the 147's. I just wish my G34 would do the same with the Sevigny's. Might be time to bust out the file.

[JHC]

Each Glock pistol is somewhat unique in this respect. I have some POA=POI with .215 and some with .245 Warren sets. Ameriglo has a wide selection of front sights. Try splitting the difference. I think they offer many sizes in the fiber optic if that's what you're looking for. The mix and match will work.

[JV_]

While shooting groups at 25 yards on an IDPA target cutting the center of the A zone in half with the sight picture I consistently shot groups roughly 4.5-5" high with 147gr Federal American Eagle.

[snip]

and picked up a Sevigny front sight with a height of .245. Heading back the range this seemed to be too far in the other direction.

I'm not sure how it could have been too far in the other direction, assuming you were using the same ammo and technique. Moving from a .215" to a .245", on a Glock 34 (7.56" sight radius), should move the POI down about 3.6" @ 25Y.

I mention technique because my groups raise by 3" if I shoot my gun with the dust cover resting on a sandbag vs supporting only my arms. I also see a much higher POI if the mag is resting on something hard.

When moving between different weight bullets (115-147), I wouldn't expect your POI to change more than an inch or two. The lighter the bullet, the lower the POI. Keep in mind - the load can make a difference too, not just the bullet weight.

FWIW: I like to setup my guns have a center hold POA=POI with 124g ammo. I do this so I'm not too far off in either direction if I change ammo/loads.

[jetfire]

FWIW: I like to setup my guns have a center hold POA=POI with 124g ammo. I do this so I'm not too far off in either direction if I change ammo/loads.

I do much the same thing but with 115 grain ammo, myself. There is something appealing to me about "put the sight in the middle of the target and that's where the bullet goes".

[ErnieB]

I do much the same thing but with 115 grain ammo, myself. There is something appealing to me about "put the sight in the middle of the target and that's where the bullet goes".

I agree!


I'm starting to think there is something larger at work here than just sight heights. As noted by JV, that much deviation in impact is odd. When I get a free second later today I'm going to detail strip the gun and take a look to see if anything is funky. I am going to head to the range this afternoon and bring some 115gr stuff with me just to compare. I am shooting a match on Saturday so I want to get this gun squared away.

Thanks for the input all!

[jetfire]

How is the barrel/slide lockup? I had an aftermarket barrel/slide combo that didn't lock up as tight as the factory, and so I had a pretty wild deviation for POI.

[ErnieB]

Spent some time at the range late yesterday afternoon. Here is the skinny:

G34 equipped with .215 height FO front, standard Sevigny rear.

- Target: IDPA

- Ammo type 1: Federal American Eagle 115gr. 5 groups of 5 rounds, POI dead on out to 25 yards

- Ammo type 2: Federal HST 147gr hollow point. 5 groups of 5 rounds, POI average about 1.5" high at 25 yards

- Ammo type 3: Federal American Eagle 147 truncated cone. 5 groups of 5 rounds, POI average 2.5" high at 25 yards. One group had a two flyers that impacted about another inch higher.

I could not believe the difference between the 115gr and 147gr AE. Is that about normal? The HST grouped the worst of the bunch. I thought it would've grouped the tightest.

[JV_]

I can easily believe 1.5" of difference between the 115 and 147.

I'd like to see the AE 147 test repeated, hopefully determining if the fliers were user error or ammo performance related.

[jetfire]

That honestly looks about right to me.

[ErnieB]

What made me scratch my head the most was the difference in deviation between the two 147gr loads. Obviously there is a projectile and velocity difference with the hotter hollow point hitting just a bit lower.

Maybe I just need to do this type of thing more often as I guess I never thought there would be a noticeable change at distances inside of 50 yards. I was wrong.

[ErnieB]

I can easily believe 1.5" of difference between the 115 and 147.

I'd like to see the AE 147 test repeated, hopefully determining if the fliers were user error or ammo performance related.

Regarding AE 147 fliers, I will re-shoot the test today but my experience has been that I seem to get a few in every box. I was benching the gun for the groups that I compared. Bye the way, I took the gun apart and it is just fine. Eliminate the variables.

[JHC]

Spent some time at the range late yesterday afternoon. Here is the skinny:

G34 equipped with .215 height FO front, standard Sevigny rear.

- Target: IDPA

- Ammo type 1: Federal American Eagle 115gr. 5 groups of 5 rounds, POI dead on out to 25 yards

- Ammo type 2: Federal HST 147gr hollow point. 5 groups of 5 rounds, POI average about 1.5" high at 25 yards

- Ammo type 3: Federal American Eagle 147 truncated cone. 5 groups of 5 rounds, POI average 2.5" high at 25 yards. One group had a two flyers that impacted about another inch higher.

I could not believe the difference between the 115gr and 147gr AE. Is that about normal? The HST grouped the worst of the bunch. I thought it would've grouped the tightest.

Sounds normal to me. I see some of the whimpy 115 grain loads print higher than some brand's (Blazer) 124 which I think is actually loaded hotter.