RO upgrades for shrinking groups

It seems that the consensus is that a new, fitted bushing is first on the list.  I was intending to get the EGW angled bore style but may not need to.
Let me know if it is worth it in the case of my new RO please.

Barrel OD     .5807
Bushing ID     .5817

And if I angle the barrel up a degree, I can no longer even feel the one mil and when I check for preload (I think gunsmiths call it spring) with barrel, bushing and slide alone, there is none so this seems perfect I suppose.

Slide ID        .7013
Bushing OD   .6984

I am not sure what Jon and other smiths feel are next in line for shrinking machine rested groups.  I recall some dude talking about an oversize slide lock pin.  I haven't gauged mine yet but it feels like at least three mils of play here.  If I trig out the impact of the slide/bushing play at fifty, then the three mils, if taken down to zero, would shrink groups by one inch.

I suppose I should also put some layout dye on upper recesses and lower lugs, shoot a couple magazines and see what we see here.  I can do that if you folks tell me what to look for.

Thoughts?
Thanks.

Have you tested it yet with premium ammo to compare too?

If your barrel to bushing is 0.001 and bushing to slide is 0.003 that’s 0.004 total. Get the new bushing.
Get the EGW 0.200 slide stop pin.
Jon

The bushing to slide fit seems a bit loose at nearly .003".

Geez, I type slow...

Jon Eulette wrote:If your barrel to bushing is 0.001 and bushing to slide is 0.003 that’s 0.004 total. Get the new bushing.
Get the EGW 0.200 slide stop pin.
Jon

When my first RO started to feel a little loose, my gunsmith told me the same thing about the stop pin. I was skeptical but did it. Wow what difference it made.

I have found Springfield slide stop pins to be as small as .195".  it will be worth your time.

David

Sure enough my ss pin is .1955-.1970 (not very round and with parting lines) and the ss pin hole in the frame can accept a .2012 so I’ll order the .200 pin that Jon recommends. When I used a .200 gauge pin to simulate the actual pin, the gun stopped short of going fully in to battery and the lower lug contour jams against the pin just shy of letting the pin seat fully in the vertical section (forward) of the lower lugs. So I replaced the .278 link with a #4 that I had on hand and all seemed well. This allowed the lugs to ride over the pin just clearing it along the outside radius. I am not sure that the link is not supporting the barrel (bad) as opposed of the lower lugs proper.  I’d like to blue everything once I get the new ss pin and make sure there is correct contact.  Sound ok?

Yes blue the ramp and see how the pin rides.  I had to do the same thing.  Larger pin would not fit with the original link.

I am not a gun smith.   We have some real pros here.

David

Obviously there’s more to it than just slapping a pin and link.
Time to have a smith do it. They have the tools and knowledge.
The factory pin dimension that’s most important, IMHO, is the diameter perpendicular (up) when it’s installed. Probably .196
A Bubba way around it is to use the .200 pin and wallow out the link to allow it to ride on the lower barrel lugs.
Again, a Bubba way

I think you can write a thesis on link fit and lower lug profiles but.. a couple of ways to see if you are riding the link at lockup..

push the slide stop pin out enough so you can swivel the end down toward the trigger guard. push the pin fully in and then rack the pistol into lockup.. now can you swivel the SS end fairly easily if not,  it's riding the link most likely.. also check to see if the SS is loose when you have the pistol in full recoil and push the barrel back. pin should be loose.. this all is easier with the recoil spring out. 

One thing I do with the barrel out is to drive the link pin out only  enough  to remove the link and then hang the link on the pin outside of the lugs.. looking from  the other side you can watch the link travel in it's arch looking for contact or lack there of...not perfect but it will get you close. at lockup you can see if the lower portion of the link is above or below the barrel lug

if you want to test it in the gun.. coat everything( slide stop pin and barrel lugs) with Dykem. let dry then assemble the pistol and cycle it 30-40 times.. put in apart and check to see the areas where the Dykem has been worn off.. or not worn off... 

A #4 link is usually .005 longer than the stock #3 link..(.283 verses .278). there are some in between links out there compared to this standard. Harrison Custom carries a .281 link. ideally the link will carry the barrel up and over the lower lug radius then set the barrel lugs down on the slide stop pin before full lockup.. not always easy...

OK, this is interesting. So for those of us following this who aren't gunsmiths but want to understand a little more about the mechanics of a 1911 and how to diagnose various issues.... if your pin is stopping on the ramp during lockup (and not firmly contacting the lower lugs, then you might need a longer link to correct this, correct?

This condition is detrimental to accuracy, right?

Yes you need a longer link or you modify the ramp.. depends on the lockup fit...another thing you can do to select the proper link is  to measure the distance from the barrel link hole.to the lockup area. Then start measuring links.the area between the link holes.. the link hole distance should be .001 or .002 shorter. Then you have to see if the link will pass over the radius of the lugs.

Riding the link at lockup while common to mass.produced 1911s is detrimental.to accuracy.  

I Literally have a collection.of makers links although EGEW, Wilson and Harrsion std. Links are.the same length. EGW does have o link and oversized links such as a 17 or 19 link.

As in .017 over the. std .278 link..not.used very often today
.

Some smiths are good enough to cut their own links from blanks.. Mr. Keefer.did that

Thank you for explaining this. This is very interesting. Not trying to derail the OP's thread, just wanted to know.

I recently picked up an RO and I am evaluating and implementing some of the suggested upgrades in this forum.

The RO is a great pistol. I should have started with one right off the bat. The one I have displays great accuracy in stock form.

jglenn21 wrote:
As in .017 over the. std .278 link..not.used very often today

I still run across high dollar custom pistols with short links; result is battered bottom barrel lugs and battered slide stop pins. It's really amazing how many smiths believe only 0.278 link should be used. I have only used on bone stock GI 1911.
Jon

Well I basically have all of my answers and thanks to dykem, jglenn21's suggestions and Mr. Kuhlnesson's amazing shop manuals, a properly cycling and except for my bushing (ordered from EGW), and with a gauge pin temporarily replacing the .200 pin (also ordered) a properly fit gun.  Now I just need my HM buddy to disinfect his Ransom machine and let me borrow it.

BTW, credit to Mr. Eulette for a lot of the link thoughts and ideas I put out.. I've been all over the place with "proper" link setup over the years bit now have seen the light so to speak..

you're right

I've found it to be not as tight as when the link is the only thing holding the barrel up. it works for me, as I don't normally have what you would call a hard fit barrel, although, I have done a few lately. I normally do these checks without the recoil spring in place just because I prefer to feel the gun going into and out of lockup in my hands.  manually locking it up without the link then with the link you can tell the difference if the link is long.  sorry for the lack of explanation.

For most folks the Dykem method is the most straight forward and fool proof.. if you don't see any Dykem being taken off from the lugs or the lug area on the pin then the link is long. 

fun fact about links is the 1911 will function without them.

I'm sort of a self taught 1911 guy other than some really good advice years ago from a AMU smith here in Ga who didn't seem to mind me hanging around and asking questions on occasion. Jon has been patient enough to answer more than a few of mine too.  I build my own pistols and help my nephews with their own builds as well as some friends..

Jimmy,

Thanks much for the response and explanation.  I too, do much of my own tuning and maintenance.  I also look for marks on the slide stop pin.  Magic marker works if Dykem isn't available and I look for marks on the top of the pin and rear after repeated cycling, to check for contact.

The deeper I went in to Mr. Kuhlnesson's manual, the less confident I felt that I'm not creating unknown reliability or accuracy issues elsewhere.  It went off to a BE smith for an accuracy job and a test target.  I've got too many hobbies as it is, to try to become a pistolsmith. "A man's got to know his limitations."