What Recoil Spring for slide mounted red dot on Mil Spec?

A number of years ago I had a gunsmith put a rail on top of my 1911 Mil Spec so I could mount a red dot.   He told me I might have to cut a few coils off the factory spring.  

I have never gotten to feed reliably.  At FTF jam or two every 100 rounds. Usually the last round in the mag.  I am now down to using a 9lb spring and I put in a buffer.  

It happens with pretty much any load/bullet, but I am currently using 4.8gr 700x and a 185 or 200gr bullet. 




I do see an 8lb spring on Midway and also a variable power recoil spring.

I did a search and found nothing.

Any advice would be appreciated.

What optic and what is your mainspring weight?

9 lbs and I am using a 30mm ultra dot

After I posted my question "similar topics" came up with another post where this was suggested...

recoil spring rate for slide mounted Ultradot? (bullseyeforum.net)

I have worked my way down from a 16 lb to the current 9lb.  After reading this I wonder if I am on the right track.  He seems to suggest it might be influenced by other factors.

How long has it been since you replaced the magazine or magazine spring?

Thanks,

I don't think I ever replaced the magazine spring.  I did check and it does do it with several different mags.  But changing a mag spring would be a cheap and easy fix to try.

Until recently I have not been a high-volume shooter.  Shoot for a few months, and then put the gun away like a fair-weather golfer.

I bought the gun about 10yrs ago and have about 6,000 rounds through it. I am retired now and shooting more. and I plan to enter a match or two at some point.  So, I need to address the issue.

if you come down on your loads to be softer.. a 11 or 12lb recoil spring coupled with a 19lb mainspring should be fine..

doubt your recoil spring has much to do with your FTF issues. the extractor tension and fit is the 1st place to look. Also is the barrel the stock barrel?  when it fails to feed what position is the round in.

I suggest it could be the 700x. I've had problems with my/that powder feeding consistantly. It could be as simple as that. I have no problem with that powder in larger charges but my Lee really doesn't work well dispensing that powder. YMMV

For mine I use a 9 pound spring, the sight is a 1 inch Match dot tube site.  I shoot 185 grain lead bullets and 3.7-3.8 grains of Bullseye and a crimp of .464-.465  A very reliable gun.

You shortened the spring and put a buffer in? First I Never use buffers, they shorten the stroke. You need extra travel to allot time for round to rise in the mag. Never cut the recoil spring, it changes the characteristics of the spring. Best to Order a spring Kit from Wolff or similar gun spring company so as to test for correct weight. I use the lightest main spring that will ignite the primers so heaviest recoil spring can be used!
 The Gunsmith you mentioned requesting that you cut the recoil spring sound like someone that does not know much about target 1911s. You might want to post a good photo of lowere barrel lug!

Has the barrel been "fit" to the gun? Is it a stock barrel or an aftermarket competition like a Kart or KKM?

Wow.  Lots of help.  I will try to be concise and address each suggestion/question.

-As I said, I am using a 9lb Wolff spring now.  I have not cut any coils on it.  

-I do use a buffer because I was paranoid about damage due to the light spring. I have not seen any evidence of it though.  I realize these may be at cross purposes so I will remove the buffer.  

-The FTF is basically where the nose of the bullet enters the chamber at too steep an angle and jams. But I will check this last batch to see if it is hanging up on the case mouth and may be a crimp thing. I tend to think not, but I was not specifically looking for that issue.

- My crimp is at around 0.469" which I have understood to be about right.  When I pull a plated .452" there is a small ring.  I would think 0.465 would be excessive and damage the bullet, but I can go ahead and give it a try.

- I have been working through an 8lb jug of 700x for a number of years since I foolishly bought an 8lb jug in the middle of a powder shortage.  I do keep pretty good records so I will check and see if I had these issues with other powders.  I check charges petty closely and generally will have a spread between 4.7 and 5.0 out of my Pro Autodisk.

- I do have Unique, Autocomp, HS-6 and 231 on hand so I will give them a try.  I do like bulkier powders as they minimize the chance of a double charge.  But I have started using a RCBS lockout die now.

- I thought the more power the better it would feed, but I can come down some on the charge of 700x.

- I have had the gun apart to put in a new hammer and beavertail, but never taken apart the mainspring housing assembly.  I heard that could be tricky and had no need to. I would expect the mains spring to be 23lbs as it is stock.

- It is a stock barrel.  The only thing not stock is the hammer and beavertail.  What would we be looking for with a picture of the barrel lug?  I ask because there is a very tiny burr on the assembly that supports the link and the lug does not swing as loosely as on my Trophy Match.  I only noticed it when I was cleaning the gun.  I was able to most of the burr out.  But I had trouble punching out the link and decided it was not worth the trouble to remove it.

- So thanks for all the help.  I will begin trying some of these suggestions, starting with the easier ones first.  I am about ready to reload another batch of rounds so I will start with the ones regarding ammo and post my results.  Might be a week or two.

Lower the mainspring to a 18 or 19lb. It is not that difficult to change, use a punch to push a the plunger down, bump the retaining pin out with another smaller punch. If you are not used to it, probably best to have the mainspring housing in a vice.

Okay. It's been a while since I had the gun apart so I will need to set aside some time for review. Midway has a 19lb Wolff spring for four bucks, so that seems like a good option to try.

Thanks

Bluesguy wrote:
-The FTF is basically where the nose of the bullet enters the chamber at too steep an angle and jams. 

This may be caused by the extractor, if the tension is too high, the rim doesn't go under the extractor and the cartridge tilts up.

Hi,

Your 1911 is a ten yrs old Mil-Spec??  Does it have the two piece Barrel?  If so, most of those have a standard JMB designed Chamber Throating.  With all other things being in spec, this type of Throating will only reliably feed 230 gr Ball Ammo.  Also, does your Mil-Spec have the Safety Lock in the Mainspring Housing?  If so, it should be removed and you install a Wolff 18 # Mainspring, a Std 1911 Main Spring Cap, and a factory Mainspring Cap Pin.  As mentioned before, the use of Buffers in a 1911 is not advised.  Also, replace the factory Magazine Follower with a Metalform Rounded Follower and don't use an 8 rd Mag.  Without having the pistol in front of me, these are the quickest suggestions I can make.

Cheers,
Roddy

It does not have a two-piece barrel. It pretty much ate whatever I fed it before I put on the Ultradot. It does indeed have a safety lock on the main spring, so I will add that the list of things to try.

Thanks to all of you for taking the time to give me so ideas of things to try.

Okay all,

I took out the buffer and ordered 18 and 19lb mainsprings and new springs for the magazines.  I will try those things first and post how it works out.

Thanks again.

Simply put I like 700X, it's all I use. I've told by a good source that Atlanta Arms was using 700X when their powder of choice was not available.

Do you find it is dirty with a fair bit of unburned powder/flakes ending up on your forearm? 

Again, I bought it because like Unique, there are loads for a lot of cartridges using it and it was during a powder shortage.  I was not planning on buying more when I finally get through this 8lb jug. 

I would be interested to know what loads you use of 185gr and 200gr plated bullets and LSWC.

Thanks,

No I don't. How much powder are you using on what bullet weight?

That information is in my original post at the top of the string, including a picture of the bullets I am using now.  I have tried a variety of 185 and 200 gr bullets.  I have gone as high as 5.5gr. with 185 Grain bullets.

I'm using 4.7gr 700x on 185gr JHP from Magnus/Zero

Well, that's about what I am using.  Don't see why a platted bullet would make too much difference.  

There might be a bit higher pressure with a jacketed bullet which could help for a more complete powder burn.  The reason I tried the higher load was because some powders burn cleaner with loads closer to full power, but it just seems like a dirty powder to me.  Kind of like Unique can be.  I just know that after a hundred rounds or so my forearm will be covered in a dozen or two flakes, and the brass is pretty dirty.

Thanks much for the feedback.

Bluesguy wrote: I would be interested to know what loads you use of 185gr and 200gr plated bullets and LSWC.

I believe most around here would advise not to bother with plated bullets for consistency/accuracy