Forcing Cone question

[hkguy]

I am shooting a 4" GP100 chambered in .357 mag. I am set up to reload .38 spl but i noticed that my gun does not like "soft" .38 spl loads. I cant keep my light loads (3.6gr W231 & 160gr LRN ~750 fps) on paper at 10 yards to save my life, including Remington 158gr LRN factory ammo. When i shoot remington 125gr +p ammo my POA and POI is spot on. My reloads that had higher velocities (4.3 W231 & 160gr LRN @ ~800 fps) also shot well. I only had time to do some informal testing for these loads and shot them free style and not off a rest. I would like to shoot the lower velocity rounds as i can get back on target faster, but its not necessarily a deal breaker for me.

Now my questions are:

Do i get my forcing cones re-cut for .38 spl or do i keep the gun as is and load for higher velocity?

Do i get a new cylinder chambered for .38 spl and swap in with the old one?

I dont have a ton of money to throw at this, just looking for some input and who ya'll would recommend for the work should i go that route.

Thanks

[Toolguy]

Ten yards is nothing. It should shoot everything you can put in it into a small group at that distance. It may be that the forcing cone needs to be recut a little bigger. This would not adversely affect the other types of ammo if kept within correct limits. No need for a different cylinder unless something is wrong with the original. 38 special is shot out of 357 chambers all the time with good accuracy.

[z40acp]

Is it throwing them all around or are they just high? A higher velocity bullet will hit lower because it is out of the barrel before it recoils up as far.

[hkguy]

Is it throwing them all around or are they just high? A higher velocity bullet will hit lower because it is out of the barrel before it recoils up as far.

the "slow" loads i shot were quite high, around 4 in high at 40 yards. this happened to me and another shooter in the same session.

[gp100man]

Both of my GP-100's are tack drivers with either .38 spl or .357 loads. But as like the guys said you will have to adjust the elevation of your sights depending on your fps. That is true with any gun. I load 158 grain lead .38 spl with Trail Boss for IDPA and those slower rounds do land quite bit higher than a full house .357 magnum round.

[hkguy]

seems i made a mountain out of a mole hill, ill go back to the drawing board and readjust as necessary.