G17 group improvement after JP Enterprises slide to frame fit work

[BigMoosie]

Here's a 25 shot group I shot the other day with the 17 at 25 yards unsupported offhand, which is substantially improved from the out of the box accuracy I was getting. The horizontal spread will tighten when I install a finer front sight blade. Prior to the slide to frame fit and trigger work done by JP Enterprises, the group would span out to the edge of the white 9 ring which has a diameter of 8 inches. The black 10 ring measures 5 inches across and the inner x ring measures 3.5 inches. Everything is stock on the gun apart from the Ghost Rocket connector. For comparison the next target is shot with my 4 inch 625 at the same distance unsupported offhand and is a 12 shot group.

Edited April 27, 2012 by BigMoosie

[jkrispies]

Thanks for the info... I might eventually do the same for my 17 as it sounds like your pre-work groups are similar to my current groups. Could I ask what your 9mm load is?

[lee blackman]

Oh wow! What all did JP do? When you say slide to frame work, do they spread the rail point on the frame that contact the slide? Kinda like an old "peen" job on a 1911?

I'm seriously considering shipping a couple of my baby's off to them now.

[BigMoosie]

Thanks for the info... I might eventually do the same for my 17 as it sounds like your pre-work groups are similar to my current groups. Could I ask what your 9mm load is?

4.5 grains of Titegroup behind 115gr Montana Gold CMJ. Check my load against the loading data before you load.

[BigMoosie]

Oh wow! What all did JP do? When you say slide to frame work, do they spread the rail point on the frame that contact the slide? Kinda like an old "peen" job on a 1911?

I'm seriously considering shipping a couple of my baby's off to them now.

I guess something like that - I asked but they didn't elaborate. Accuracy wise it's like night and day compared to what it was shooting like straight out of the box. Being a new Glocker I must admit I was really disappointed when I first got the gun. Now it shoots acceptably well.

Edited April 27, 2012 by BigMoosie

[usmc0326]

Thanks for the info... I might eventually do the same for my 17 as it sounds like your pre-work groups are similar to my current groups. Could I ask what your 9mm load is?

4.5 grains of Titegroup behind 115gr Montana Gold CMJ. Check my load against the loading data before you load.

I would take a look at your overall length. I did some testing with OAL from max to about 20 and the shorter rounds were more accurate in my glocks. I was getting 5 inch groups with winchester white box. 124 grain mg, 5.5 grains of power pistol at 1.120(iirc) and we are under 2 inches. Even winchester white box bullets 115gr, 4.0-4.5 tg, and 1.135 oal I was in the 2.75 inch group range.

My top end is stock, the only change I made to the upper is the recoil spring and guide rod. If you take some time and dial in the load with testing glocks are surprisingly accurate out of the box.

Edited April 28, 2012 by usmc0326

[BigMoosie]

Thanks for the info... I might eventually do the same for my 17 as it sounds like your pre-work groups are similar to my current groups. Could I ask what your 9mm load is?

4.5 grains of Titegroup behind 115gr Montana Gold CMJ. Check my load against the loading data before you load.

I would take a look at your overall length. I did some testing with OAL from max to about 20 and the shorter rounds were more accurate in my glocks. I was getting 5 inch groups with winchester white box. 124 grain mg, 5.5 grains of power pistol at 1.120(iirc) and we are under 2 inches. Even winchester white box bullets 115gr, 4.0-4.5 tg, and 1.135 oal I was in the 2.75 inch group range.

My top end is stock, the only change I made to the upper is the recoil spring and guide rod. If you take some time and dial in the load with testing glocks are surprisingly accurate out of the box.

I was running loads from 1.125 to 1.155 and with a combination of different bullets weights to see if this would improve accuracy. I've never known a handgun to be so particular about its loads especially offhand. I've settled on 1.150 using 115gr MGs, but the change in accuracy came when I got the gun back from JP. The Glock is designed to run on any diet of ammunition though.

Edited April 28, 2012 by BigMoosie

[jkrispies]

Thanks for the info... I might eventually do the same for my 17 as it sounds like your pre-work groups are similar to my current groups. Could I ask what your 9mm load is?

4.5 grains of Titegroup behind 115gr Montana Gold CMJ. Check my load against the loading data before you load.

I would take a look at your overall length. I did some testing with OAL from max to about 20 and the shorter rounds were more accurate in my glocks. I was getting 5 inch groups with winchester white box. 124 grain mg, 5.5 grains of power pistol at 1.120(iirc) and we are under 2 inches. Even winchester white box bullets 115gr, 4.0-4.5 tg, and 1.135 oal I was in the 2.75 inch group range.

My top end is stock, the only change I made to the upper is the recoil spring and guide rod. If you take some time and dial in the load with testing glocks are surprisingly accurate out of the box.

I'was running loads from 1.125 to 1.155 and with a combination of different bullets. I've never known a handgun to be so particular about its loads especially offhand. I've settled on 1.150 using 115gr MGs, but the real change in accuracy was when I got the gun back from JP.

Yeah, I'm down to 1.060 OAL with Precision Delta 124gr JHP's. I also started at 1.125 and the groups shrink decidedly as the OAL lowers (I haven't the slightest idea why this is true) but I'm thinking I can only go so deep with these things... I did have a better load using Zeros, but I gave up on trying to find any, especially at a price even close to the Precision Deltas.

[BigMoosie]

Yeah, I'm down to 1.060 OAL with Precision Delta 124gr JHP's. I also started at 1.125 and the groups shrink decidedly as the OAL lowers (I haven't the slightest idea why this is true) but I'm thinking I can only go so deep with these things... I did have a better load using Zeros, but I gave up on trying to find any, especially at a price even close to the Precision Deltas.

I think I have seated bullets out as far a 1.155 and I'm still not touching the lands. I personally don't think one's going to see a massive accuracy difference with changes to bullet seating depth at the distances handgunners typically shoot at, especially with a Glock. But I could be wrong.

Edited April 28, 2012 by BigMoosie

[jkrispies]

Yeah, I'm down to 1.060 OAL with Precision Delta 124gr JHP's. I also started at 1.125 and the groups shrink decidedly as the OAL lowers (I haven't the slightest idea why this is true) but I'm thinking I can only go so deep with these things... I did have a better load using Zeros, but I gave up on trying to find any, especially at a price even close to the Precision Deltas.

I think I have seated bullets out as far a 1.155 and I'm still not touching the lands. I personally don't think one's going to see a massive accuracy difference with changes to bullet seating depth at the distances handgunners typically shoot at, especially with a Glock. But I could be wrong.

I thought so too until I took the newly loaded 1.125" ammo to my Steel Challenge to test fire and re-zero. I figured it wouldn't be perfect without some work but it would at least be usable till I got the recipe perfected. I'm glad I was (mostly) by myself because I knew I was a better shot than the results I was getting. There's no way I could have shot an SC course with that ammo without looking like a complete fool.

Edited April 29, 2012 by jkrispies

[Jonathan Taliani]

Yeah, I'm down to 1.060 OAL with Precision Delta 124gr JHP's. I also started at 1.125 and the groups shrink decidedly as the OAL lowers (I haven't the slightest idea why this is true) but I'm thinking I can only go so deep with these things... I did have a better load using Zeros, but I gave up on trying to find any, especially at a price even close to the Precision Deltas.

I think I have seated bullets out as far a 1.155 and I'm still not touching the lands. I personally don't think one's going to see a massive accuracy difference with changes to bullet seating depth at the distances handgunners typically shoot at, especially with a Glock. But I could be wrong.

I thought so too until I took the newly loaded 1.125" ammo to my Steel Challenge to test fire and re-zero. I figured it wouldn't be perfect without some work but it would at least be usable till I got the recipe perfected. I'm glad I was (mostly) by myself because I knew I was a better shot than the results I was getting. There's no way I could have shot an SC course with that ammo without looking like a complete fool.

I wonder if that may be a gun or load/bullet issue. I've put many thousands of rounds loaded at 1.145 through several Glocks, but mainly my G34, without issue. This is with 115, 124, and 147gr bullets as well as JHP, FMJ, and Moly.

[jkrispies]

So maybe I need to go longer rather than shorter??? It seems like the consensus has been towards a shorter OAL...

[usmc0326]

The offhand and Ransom Rest testing I have done with OAL in my glock 17, 34's have shown that shorter oal are more accurate with the same powder charges... I started at max oal, with the same powder charge and only varied the oal and the groups tightened. Starting at ~1.165 (if I recall correctly) and went down to 1.130. Groups started at about 5 inches and went down to 2.75 at the shorter oal at 25 yards. Also I found that best accuracy was either above or below the trans/ supersonic transition. Naturally every weapon is a bit different but overall with the stock barrel I was able to get groups as small as ~1.25 with 10 rounds at 25 yards, the best repeatable was ~1.50. My uspsa production loads (shoots clean, low recoil, accurate, and cycles quickly) are with variants of 124gr, 147gr and N320/ power pistol. Generally I am satisfied with 2 inches or less at 25 with my stock barreled Glock race pistols. My favorite carry round also shoots under 2 inches. These are all shot with stock top ends (barrel, slide/ frame fit is unchanged from factory) and federal (FC headstamp) range brass cleaned with stainless media, winchesterSP primers (cheap and decent es/sd for when I can't get federal SP).

So I am a bit skeptical of having to pay someone a bunch of money to get 2 inch groups out of my glocks when some time and attention to detail

Sidebar- if anyone wants me to test their bullets or components feel free to send them to me

Edited April 30, 2012 by usmc0326

[BigMoosie]

The offhand and Ransom Rest testing I have done with OAL in my glock 17, 34's have shown that shorter oal are more accurate with the same powder charges... I started at max oal, with the same powder charge and only varied the oal and the groups tightened. Starting at ~1.165 (if I recall correctly) and went down to 1.130. Groups started at about 5 inches and went down to 2.75 at the shorter oal at 25 yards. Also I found that best accuracy was either above or below the trans/ supersonic transition. Naturally every weapon is a bit different but overall with the stock barrel I was able to get groups as small as ~1.25 with 10 rounds at 25 yards, the best repeatable was ~1.50. My uspsa production loads (shoots clean, low recoil, accurate, and cycles quickly) are with variants of 124gr, 147gr and N320/ power pistol. Generally I am satisfied with 2 inches or less at 25 with my stock barreled Glock race pistols. My favorite carry round also shoots under 2 inches. These are all shot with stock top ends (barrel, slide/ frame fit is unchanged from factory) and federal (FC headstamp) range brass cleaned with stainless media, winchesterSP primers (cheap and decent es/sd for when I can't get federal SP).

So I am a bit skeptical of having to pay someone a bunch of money to get 2 inch groups out of my glocks when some time and attention to detail

Sidebar- if anyone wants me to test their bullets or components feel free to send them to me

Thanks, that's interesting I'm running 1.150 at the moment and will try 1.130.

[gose]

The offhand and Ransom Rest testing I have done with OAL in my glock 17, 34's have shown that shorter oal are more accurate with the same powder charges... I started at max oal, with the same powder charge and only varied the oal and the groups tightened. Starting at ~1.165 (if I recall correctly) and went down to 1.130. Groups started at about 5 inches and went down to 2.75 at the shorter oal at 25 yards. Also I found that best accuracy was either above or below the trans/ supersonic transition. Naturally every weapon is a bit different but overall with the stock barrel I was able to get groups as small as ~1.25 with 10 rounds at 25 yards, the best repeatable was ~1.50. My uspsa production loads (shoots clean, low recoil, accurate, and cycles quickly) are with variants of 124gr, 147gr and N320/ power pistol. Generally I am satisfied with 2 inches or less at 25 with my stock barreled Glock race pistols. My favorite carry round also shoots under 2 inches. These are all shot with stock top ends (barrel, slide/ frame fit is unchanged from factory) and federal (FC headstamp) range brass cleaned with stainless media, winchesterSP primers (cheap and decent es/sd for when I can't get federal SP).

So I am a bit skeptical of having to pay someone a bunch of money to get 2 inch groups out of my glocks when some time and attention to detail

Sidebar- if anyone wants me to test their bullets or components feel free to send them to me

Interesting that you got good results from a RR. When I ran a bunch of tests in a RR, I realized I could shoot better groups (and really good ones) from a sandbag. I figured that was because of the somewhat sloppy fit between frame and barrel/slide which made it look like the accuracy wasnt there. Sloppy fit between frame and slide might mean that the slide doesnt align exactly the same way every time, which would explain larger groups in a ransom rest where the frame is fixed. That fit wont be as detrimental to accuracy when shooting from a sandbag, since you'll actually adjust your aim between shoots and as long as barrel/slide fit is good, accuracy will be there.

So, I'm somewhat sceptical about accuracy improving a lot by tightening up slide to frame fit, since my experience says that it doesnt really matter much. Maybe they did something more than just tightening up the fit, but thats how its marketed?

[usmc0326]

edit, after looking my glock 17 load is actually 1.120 that I am running. But I am in the middle of testing new powders so stay tuned.

Ransom rest testing can be VERY tricky with polymer frames due to the clamping of the frame and the frame giving. 1911 testing is cake.

gose-

Slide tightening works by reducing the clearances. It works but for it to be practical you have to have a barrel / weapon that is being limited by the slide resetting in different positions every time. So all accuracy is is simply... repeatability. So as long as the slide locks up the same way, the barrel prints the same place, the frame is pointed in the same place, good trigger squeeze straight to the rear and the pistol recoils the same way while the bullet is still in the barrel... you get accuracy. Glocks factory barrels are some of my favorite factory pieces around. Good coatings and good manufacturing makes for good repeatability. Part of the reliability comes from having larger clearances than would be ideal for peak accuracy. But there is a bit of a trade off with the two. When you tighten the slide your increasing accuracy if properly performed, however your reducing the distance between metal parts... So possibly reducing reliability. When your factory barrel is the limiting factor in a stock pistol, there isn't really any sense in getting the slide tightened unless you have an exceptional barrel. Hence when your running a barrel like a custom fit barsto, a slide fitting would be beneficial to overall accuracy and you could see a 1.125 inch consistent group at 25 yards with a glock (way better than most people can even shoot to begin with).

[BigMoosie]

edit, after looking my glock 17 load is actually 1.120 that I am running. But I am in the middle of testing new powders so stay tuned.

Ransom rest testing can be VERY tricky with polymer frames due to the clamping of the frame and the frame giving. 1911 testing is cake.

gose-

Slide tightening works by reducing the clearances. It works but for it to be practical you have to have a barrel / weapon that is being limited by the slide resetting in different positions every time. So all accuracy is is simply... repeatability. So as long as the slide locks up the same way, the barrel prints the same place, the frame is pointed in the same place, good trigger squeeze straight to the rear and the pistol recoils the same way while the bullet is still in the barrel... you get accuracy. Glocks factory barrels are some of my favorite factory pieces around. Good coatings and good manufacturing makes for good repeatability. Part of the reliability comes from having larger clearances than would be ideal for peak accuracy. But there is a bit of a trade off with the two. When you tighten the slide your increasing accuracy if properly performed, however your reducing the distance between metal parts... So possibly reducing reliability. When your factory barrel is the limiting factor in a stock pistol, there isn't really any sense in getting the slide tightened unless you have an exceptional barrel. Hence when your running a barrel like a custom fit barsto, a slide fitting would be beneficial to overall accuracy and you could see a 1.125 inch consistent group at 25 yards with a glock (way better than most people can even shoot to begin with).

What bullets are you using?

[usmc0326]

edit, after looking my glock 17 load is actually 1.120 that I am running. But I am in the middle of testing new powders so stay tuned.

Ransom rest testing can be VERY tricky with polymer frames due to the clamping of the frame and the frame giving. 1911 testing is cake.

gose-

Slide tightening works by reducing the clearances. It works but for it to be practical you have to have a barrel / weapon that is being limited by the slide resetting in different positions every time. So all accuracy is is simply... repeatability. So as long as the slide locks up the same way, the barrel prints the same place, the frame is pointed in the same place, good trigger squeeze straight to the rear and the pistol recoils the same way while the bullet is still in the barrel... you get accuracy. Glocks factory barrels are some of my favorite factory pieces around. Good coatings and good manufacturing makes for good repeatability. Part of the reliability comes from having larger clearances than would be ideal for peak accuracy. But there is a bit of a trade off with the two. When you tighten the slide your increasing accuracy if properly performed, however your reducing the distance between metal parts... So possibly reducing reliability. When your factory barrel is the limiting factor in a stock pistol, there isn't really any sense in getting the slide tightened unless you have an exceptional barrel. Hence when your running a barrel like a custom fit barsto, a slide fitting would be beneficial to overall accuracy and you could see a 1.125 inch consistent group at 25 yards with a glock (way better than most people can even shoot to begin with).

What bullets are you using?

match ammo is montana gold JHP 125gr/ cmj 147, practice I use Bayou Bullets polymer coated lead bullets.

[gose]

So as long as the slide locks up the same way, the barrel prints the same place, the frame is pointed in the same place, good trigger squeeze straight to the rear and the pistol recoils the same way while the bullet is still in the barrel... you get accuracy.

Not really disagreeing, just saying that the frame to slide fit usually isnt the most important piece of the puzzle.

[usmc0326]

So as long as the slide locks up the same way, the barrel prints the same place, the frame is pointed in the same place, good trigger squeeze straight to the rear and the pistol recoils the same way while the bullet is still in the barrel... you get accuracy.

... usually isn't the most important piece of the puzzle.

Agreed

[slobberbone]

usmc0326

How much difference in accuracy do you see between the Montana Gold and Bayou Bullets loadings?

[BigMoosie]

usmc0326

How much difference in accuracy do you see between the Montana Gold and Bayou Bullets loadings?

I`ve tried 1.120 OAL but 1.150 delivers the best accuracy out of my G17.