FrankD

Hi hanexp, You answered my email on troubleshooting my SVI open gun last month. I'm still playing with powder. I did use 3n38 and 3n37. The gun to my surprise didn't like the 3n38 starting with 9.0 grs. I when up to 10 grains with a hard hitting impact to the hand and muzzle flip.

I had better luck with 3n37 which SVI's website recommends for guns with no holes in the barrel. Still fine tuning that powder.

My gun does not have any holes in the barrel just a 3 hole comp. I noticed that the hammer spring take some effort to over come if you cock the gun by hand. SVI uses a 17 lb. hammer spring. I ordered a 15 and 17 lb. hammer springs from Dawson a few days ago. I think the hammer spring I removed took too much powder to overcome the spring that was in the gun.

What is your thoughts on lowering the grains and going to a 15 lbs. spring. I was wondering if you ever went down this road with your gun?

I think some of the information I provided was not clear on my part. I should have mentioned that the gun had no holes in the barrel.

Thanks,

Frank

Thanks Mike for the information.

 My SVI is a early model with no holes in the barrel just a compensator.

I tried 3N38 once with not much luck at 9.0 grs. SVI recommends 3n37 for barrels with just a compensator. I had better luck with 3N37with 9.2 grains using a 124 gr FMJ. I also tried Auto Comp with 6.0 grs. yesterday and its just not enough powder.

SVI also recommends a 17lbs. hammer spring. The spring in the gun made the hammer very hard to pull back using your thumb. I installed a 15 lbs. spring with the Auto Comp at 6.1 grains.The max load according to Hodgdon Reloading Sheet is 6.3 grains. Seems to me still not enough powder.

So I plan on going to 6.3 and 6.5 grs. of Auto Comp. Atlas Gunworks suggested Silhouette powder. He presently building me a 9mm IDPA/USPSA gun from a STI Frame Kit that I've had hanging around for a few years.

Hi hanexp, You answered my email on troubleshooting my SVI open gun last month. I'm still playing with powder. I did use 3n38 and 3n37. The gun to my surprise didn't like the 3n38 starting with 9.0 grs. I when up to 10 grains with a hard hitting impact to the hand and muzzle flip.

I had better luck with 3n37 which SVI's website recommends for guns with no holes in the barrel. Still fine tuning that powder.

My gun does not have any holes in the barrel just a 3 hole comp. I noticed that the hammer spring take some effort to over come if you cock the gun by hand. SVI uses a 17 lb. hammer spring. I ordered a 15 and 17 lb. hammer springs from Dawson a few days ago. I think the hammer spring I removed took too much powder to overcome the spring that was in the gun.

What is your thoughts on lowering the grains and going to a 15 lbs. spring. I was wondering if you ever went down this road with your gun?

I think some of the information I provided was not clear on my part. I should have mentioned that the gun had no holes in the barrel.

Thanks,

Frank

Thanks Mike for the information.

 My SVI is a early model with no holes in the barrel just a compensator.

I tried 3N38 once with not much luck at 9.0 grs. SVI recommends 3n37 for barrels with just a compensator. I had better luck with 3N37with 9.2 grains using a 124 gr FMJ. I also tried Auto Comp with 6.0 grs. yesterday and its just not enough powder.

SVI also recommends a 17lbs. hammer spring. The spring in the gun made the hammer very hard to pull back using your thumb. I installed a 15 lbs. spring with the Auto Comp at 6.1 grains.The max load according to Hodgdon Reloading Sheet is 6.3 grains. Seems to me still not enough powder.

So I plan on going to 6.3 and 6.5 grs. of Auto Comp. Atlas Gunworks suggested Silhouette powder. He presently building me a 9mm IDPA/USPSA gun from a STI Frame Kit that I've had hanging around for a few years.