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new 6" GP100.... ammo question

7K views 19 replies 16 participants last post by  sybo 
#1 · (Edited)
I just bought a new 6" blued GP100 (first revolver) and am currently gathering up some ammo to go test it out

Judging from some research, it seems that the gun is sighted in for 158 grain 357 mag ammunition from the factory. How far "off" should I expect 130 grain 38 special loads be at, say, 15 yards? What about 125 grain 357 mag?

I plan on shooting 158 grain 38 special the most out of the gun once I start reloading my rounds.... so for long term, I don't want to mess with the factory sight-in. I'd just like to know about how far off my POI should be in elevation. Are we talking 1", of more like 3" or 4"? I'm not sure just HOW big of a difference grain makes at such small yardage
 
#3 ·
Do yourself a BIG favor, as I do, and NEVER use .38 Special cases in it. Instead, use .357 mag cases ONLY and use whatever loads you want, whether they are .38 spl or .357 mag. That way, you eliminate the possibility of the "dreaded" ring caused by firing .38's in your .357. The .357 is about .120" inch longer than a .38 spl., and using the shorter cases could theoretically cause that powder ring in your cylinder. If you use the .357 mag cases, you eliminate the ring because the cylinder was made to accomodate the longer .357 case. This all assumes one will do their own reloading, which is 'way cheaper and more controllable. Since there is no semi-auto ejection situation, reusing one's brass is super-simple.
 
#14 ·
QFT. I have been shooting noting but +P in my 4 inch GP. And after each session I use various brushes to clean it. When I'm done it's clean as new. Sometimes you can't use .357 at a range. Does that mean you don't shoot that gun? I think not. If you have a good cleaning regimen after using any gun, this shouldn't be a problem. OTOH if you don't clean you get problems.
 
#6 ·
Spend some extra money and get the Hoppe's Viper Bore Snake and you'll never have to worry about carbon ring in your cylinder...as long as you clean your gun after every shooting session. I've ran 5000 rds of 38's in my SP 101 357 mag and my cylinders are spotless. Also, you might enjoy reloading 38's with 148 gr wadcutters...those make very nice holes in paper and are very easy to shoot accurately.
Hope this helps.
 
#17 ·
38 Hollow base wadcutters HBWCs make a perfect home defense round. They won't go through walls with minimum muzzle flash and they leave a nasty wound. I once reloaded some HBWCs and turned the bullet around with the hollow end out. I shot some of them into a 5 gal metal bucket, they did very well, made some ugly odd shaped holes. I would pity anyone hit with one of these.
 
#7 ·
Congrats on the new GP! I've got a regular 3" GP100 .357 mag and a Wiley Clapp edition 3". I've been jonesing for a longer barrel. I probably won't go with 6" but try and find one of the few 5" models hiding out there. Oh, how I wish Ruger would make 5" GP's.
 
#8 ·
Brandi,

Ruger does make a 5", I've got one and I and everyone else that tries it loves it! It is a Davidson's exclusive, and you or you dealer can order it. Once i saw one at the range I had to have it! I picked one up a couple of months ago for $648. (Davidson's also gives a lifetime Gaurantee for any weapon purchased through them for repair or replacement - pretty cool!)

ZoSo- why worry about adjusting you sight? That's what it's for. Once you get it dialed in leave it alone, but until then have at it!

I'm shooting 158gr. SJSP in both .357 and .38, with the magnums dialed in for zero @ 25 yds. ( drop 1.4 at 50yds ). The +P .38 is pretty much dead on (maybe a touch lower), at 25 with a 2.75 drop at 50

I wouldn't worry about carbon rings shooting .38's just clean it when you get home and its good as new. People have been doing it forever, I've shot with guys mixing 38's in their guns for 30 years and their guns are fine. It was part of the reason I got mine, it's like getting 2 guns in one!
 
#10 ·
ZoSo- why worry about adjusting you sight? That's what it's for. Once you get it dialed in leave it alone, but until then have at it!

I'm shooting 158gr. SJSP in both .357 and .38, with the magnums dialed in for zero @ 25 yds. ( drop 1.4 at 50yds ). The +P .38 is pretty much dead on (maybe a touch lower), at 25 with a 2.75 drop at 50
I didn't want to adjust away from 158 grains because that's what I plan on shooting out of it long term... I just have this particular ammo now because it's all I could find on the shelves. I hate to go through the trouble of sighting in a box of 130 gr 38 and 125 gr 357 only for one box of each, then go right back to the original sight-in for 158.

Just curious how big of a POI change I would expect at like 15 yards... wouldnt imagine much, but I don't really know. Judging from the responses here, I shouldn't expect a heck of a lot.
 
#13 ·
I'm getting rubber/wood-insert grips from Altamont, who made the original style grips for the GP100. The stock Hogues are waaayyy to thin for me. I have to fumble around for a minute to get a proper grip on them. They just don't work for my hands

The rubber grip will have "snakeskin" patterning, and I'm getting smooth silver/black wooden inserts. Ought to look pretty sharp on a blued model
 
#15 ·
Choose the ammunition that works best ballistically/terminal performance-wise for the function that you're using your GP100 for. Then zero the sights-zeroing sets the gun's sights accommodating both you (your unique physique/index) and the cartridge's performance at the range desired, to achieve an identical Point of Aim/Point of Impact (POA/POI).

The factory setting my be a convenient place to start-but it's up to you to verify and finalize to your specifics. That's one of the advantages of having an adjustable-sight gun; with a fixed sight gun, its often a file/and or gunsmithing kinda day...

Most Rugers, in my experience, have factory settings for the GP100s set primarily for a six-o-clock POA for a center-of-target POI with 158gr .357 ammunition (or 158 gr .38 Special if the GP is chambered specifically for .38 Special); for defensive use, I much prefer a center-hold POA/POI-I think that it's much more instinctive. Target shooters may prefer the six-o-clock hold.

Best, Jon
 
#19 ·
I agree with blackvoid. Use .357 magnum cases in your .357 revolver.

You will not know you have a problem with the chamber fouling until you shoot a cylinder of full house 158 Gr. .357 magnum rounds and are unable to get the ejector to work.

The revolver will be unuseable at that point until you get it to a shop and tap each stuck case out of each chamber.

That will teach you a lesson. This is something you learn the hard way.
 
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