Am I having a barrel lockup issue?

I did the unthinkable and changed 2 things at the same time on my SA 5" RO 9mm.  My range visits go from great sessions to "what the heck is going on?"
The 2 things were installing an EGW angle-bore thick-flange bushing and a FF3 3 MOA red dot.  At times I get 4 shots in a C to C 3/4" group and a flyer out 2" high 11:00 to 2:00;: other times 2 distinct groups 2 to 3" apart at 12:00; still other times a 1 1/2 to 2 1/2" line of 5 shots stacked at 12:00; and sometimes all shots groups are 2" above zero.   All this occurring on benchrest at 25 yds.   Yesterday I shot at 50 yds and got 3 holes touching 4" above 25 yd. zero.

All my ammo is 115 JHP, 4.1 TG, 1.120 COL, sorted brass by brand and times fired, no crimp.  I do experiment with other loads and bullets but the aforementioned is my go-to load recipe.

I have examined the barrel and slide lugs under 5X mag and see no anomalies.  All lug edges are clear and sharp exhibiting no galling nor roughness.
SA refit the slide to the frame and put in a new barrel at 600 rounds.  I've since added 500 rounds.   The FF3 screws did loosen after 150 rounds and I blue Loctited them checking after every session and both are remaining tight.   I have replaced the stock SA bushing and the groups are too large to draw a conclusion.

I can only surmise the barrel lugs are not seating all the way into the slide lug slots and pointing the barrel slightly above the gun's normal zero.

I welcome any suggestions, questions or comments to help me solve this problem. You folks and this forum have been an immense help in the past and I thank you.

Dave

Hope Jon, Jerry, or KC will comment here.  I suspect barrel springing with the new bushing.  Bushing replacement almost always requires relieving the bushing interior so the barrel can go in and out of lockup without springing.  Even an angle bored bushing can need this because the barrel has to rotate in and out of lock. Put the old bushing back in and retest; if it is like it used to be you have eliminated the sight as the problem source.

I doubt its the dot so that leaves the bushing, change it back and retest

What is the oal length of the last round in the magazine before firing.

Just questioning the "no crimp"

Like David said, put in the old bushing and see what happens.

james r chapman wrote:What is the oal length of the last round in the magazine before firing.

Just questioning the "no crimp"

Like David said, put in the old bushing and see what happens.

All my rounds under discussion are 1.120 in. COL.  Yes David and James,  I will repeat the test I made with the stock SA bushing I ran last week.   I really was careful about barrel springing when I installed the bushing.  I feel absolutely no resistance when racking manually and the only issue I've had with cycling recently is the slide locking back when I have a round(s) in the magazine.  It happened twice in the last 2 weeks, not sure what that is about as it has never happened before and I've had the EGW bushing in since 6/27 or thereabouts.   I'll post the results of the bushing test I run tomorrow.  I've got to load up some rounds today.  Hope I can hold my throws consistently in this hot, humid weather.   David, my no crimp just brings the mouth down to the diameter of the section of the case where the bullet is seated to remove any chance of pressure changes.

When I use to load for my 9mm beretta 92 , I tried the no crimp that David Sams recommended and had mixed results, so I called him and asked him about the "no crimp" info, he said he does use a crimp die but only to remove any case belling so in reality it was a very minor crimp, once I started doing that my rounds were more consistent.

I reran the SA stock bushing vs. EGW's.   Ever talk about a problem and have it disappear?  Cautious optimism here as I still don't understand what's going on.  I took DRDon's suggestion by seeing if the barrel properly seated with the bare slide and bushing and did not need a "push" to bottom out and also did that with the stock bushing.  There was no difference between the 2 bushings as both bottomed out with no pressure.  I also repeated racking with no recoil spring in place and found no resistance except for the disconnector with both bushings.

The Data.  I do not always use the standard circular group measurement so I can give you an idea of shot placement.  I haven't learned how to post photos. 

My targets consist of a plus sign with 1/4" thick legs 8" in x and 9 1/2" in y.  Red dot POA at center of cross.   I shot 10 rounds per target, 5 per mag on a bench/pistol rest. All 30 rounds were 1x-fired Rem. brass, Everglades 115 JHP, 4.1 grn. Titegroup, 1.120 COL, no crimp (just flare removal).  A variable wind of about 5 mph, 75-82 deg. F.

Target A 25 yds with SA bushing yielded 9 shots c-to-c in an upright rectangle 1 1/4" wide, 2 1/4" high.  1 flyer 2 1/2" below the group center at 6:00.

Target B 25 yds with EGW bushing had 8 shots c-to-c in a prone rectangle 1 7/8" wide, 1" high.  2 flyers 1 1/2" & 2 3/8 " above the center at 12:00.

Target C 50 yds with EGW bushing yielded 7 shots in an almost-circular c-to-c 1 3/8" group.  3 flyers; 2" from group center 5:00, 2 1/2" from ctr. at 3:00 and 3" from ctr. at 12:00.

Conclusions?  Just to say I prefer the EGW bushing.  I'm not counting my chickens yet.  I'll probably rerun the EGW cells with 20 shots each and either declare victory and move on or have more questions.   Thank you for your thoughtful suggestions and comments.  I welcome more advice if there is anyone out there willing to give it.   Thanks again.

Dave