PDA

View Full Version : Bolt over Base malfunction



Calokie
30th April 2006, 16:20
I have a Colt Officers model and it appears that I am having Bolt Over Base malfuctions on the last round in my magazine.

Background:
-New Wilson Combat reverse plug guide rod and spring installed
-New Ed Brown extractor installed
-Gap between barrel and feedramp appears to be within spec
-Using new 7 rnd Wilson magazines
-Shooting Winchester light factory target ammo

The slide appears to be catching the extractor groove on the case and pushing the round up into the feedramp and JAM! The malfuction is cleared easily. The extractor tention does not appear too tight.

This happened today about 4 or 5 times out of 100 rounds. I've not had the gun long and I haven't put many rounds through it. I've read a few posts about limp wristing, and I suppose that could be my problem.

I need some advise as far as: (1) Mechanically, what could be happening to the gun that I need to have fixed?, (2) If I am limp wristing the gun, is there anything I can do mechanically to mitegate this problem? I don't want to worry about holding the gun "just right" to avoid a jam in the middle of a situation when I need the gun to function properly? (3) Finally, if I need to have experts work on the gun, who do you recommend?

Thanks for the help

wichaka
30th April 2006, 17:02
Thats not a "bolt over base" that's a fail to feed problem. O bolt over base, is when the slide runs up over the base of the round its trying to feed.

The extractor should have 1 1/2 - 1 3/4lbs of tension.........or check the tech section for the proper adjustment without a gauge.

I doubt its limp wristing, I've been with some gunsmiths one time and we tried to get several guns to malfunction by "limp wrisitng"........its pretty tough to do. Althoug smaller guns are more apt to have it.........

Can you post a pic to show exactly what position the round is stopping?

Calokie
30th April 2006, 17:45
I'm too low tech to be able to post any pictures, sorry.

I guess I've confussed BOB with a simple FTF issue. I'll try to clarify the problem.

The last round in mag is partly still in the mag with the nose riding up the feedramp. The slide is on top of the rear of the case. It looked like the slide caught the case at the extractor groove, or somewhere other than the rear of the case, and began pushing the round forward. In one or two instances, the round was completely out of the mag and bound up between the feedramp and the slide, with the slide on top of the rear of the round. I hope this helps describe my problem.

LeeCreekKid
30th April 2006, 19:26
How old it this gun? It could be a weak mag spring. The spring is at it's weakest on the last round.

Hersh
30th April 2006, 20:39
Calokie,

Here's a thread I have bookmarked that will show you what a bolt-over-base looks like. http://forum.m1911.org/showthread.php?t=9588This might help you describe the failure you're having.

Personally I'm very visual and it's easier for me to explain/understand if I have a pic. If you have a digital comera posting pics in your messages is a snap. Instructions can be found in the FAQ section.

http://forum.m1911.org/faq.php?

Hth,

Hersh

wichaka
30th April 2006, 21:41
Ok.......that is a bolt over base. Your first post sounded like the extractor was hooking onto the case rim properly..........

Yes, it is a magazine problem...........specifically a weak mag spring. Get new ones, or some xtra power springs if they make them for Wilsons.

1911Tuner
30th April 2006, 22:07
Did somebody say...Wilson? :D

wichaka
1st May 2006, 00:17
Did somebody say...Wilson? :D


I knew that would draw you out of the woodwork! :D

Me thinks I remember a few posts about some certain flat follower type mags that needed some xtra power springs in them........hmmmmmm what was the make of that company...........some kind of metal something............. :D

John
1st May 2006, 02:38
Wilson 7 rounders in an Officers size pistol Johnny.

Calokie, try using a standard 6 round Officers magazine, new if possible.

Also, what recoil spring do you have in the pistol (since you said you changed the guide rod and spring).

1911Tuner
1st May 2006, 05:05
Wilson 7 rounders in an Officers size pistol Johnny.

Calokie, try using a standard 6 round Officers magazine, new if possible.

Also, what recoil spring do you have in the pistol (since you said you changed the guide rod and spring).

7-round OM-sized mags have the same quirks as standard-length 8-round mags...They were designed as 6-round mags, and, in 6-round capacity with the proper follower and a good spring, work pretty well in the chopped variants.

Wichaka... :D

Truth is that most 1911 magazines could use better springs. McCormick's Powermag is an exception, but they've still got that abominable Devel follower...

John
1st May 2006, 07:22
Johnny, can the bolt-over-base be caused by too strong a recoil spring? Or is it always a weak magazine spring causing it?

1911Tuner
1st May 2006, 07:53
Johnny, can the bolt-over-base be caused by too strong a recoil spring? Or is it always a weak magazine spring causing it?

Sure can. Basically, the slide is outrunning the magazine on the return to battery, and an overly stout recoil spring drives the slide faster. Most of the time, a good mag spring will cure it though. With a Wolff mag spring, by the time you could find a recoil spring that was strong enough to cause it, you'd probably be into short recoil...which can also cause a bolt-over base FTF.

wichaka
1st May 2006, 10:59
McCormick's Powermag is an exception, but they've still got that abominable Devel follower...


Now this my friend, is where we both agree about the same thing when it comes to magazines.

Calokie
1st May 2006, 16:52
The mags I am using are band new Wilson 7 rounders. I will take your suggestion and by some extra power springs to see if that resolves the problem.

The guide rod spring is what Wilson sent with the new rod,..I'm not certain of the spring weight, but I'll try new mag springs first before I start down another road.

I've heard people mention Metalform,...it that the perferred place to get good springs? Also, do I need to get new followers as well, or will the spring just slap right into the Wilson mags?

wichaka
1st May 2006, 20:46
If my guess is right, Wilson packages their Officers rods with 24lb springs........which 22lbs is factory........so 2lbs over what they should be. 2lbs is a lot for such a light weight slide.

Brownells has a 22lber for about 8.00 + shipping. Part number #969-423-220

If your mags are new........try the lighter recoil spring first, me thinks that might solve the problem.

1911Tuner
1st May 2006, 22:15
May I have your attention please...

Magazines for the Officer's Models...Defenders...MIcros, et al were designed as 6-round magazines. If the Wilson 7-round magazines are the shortened, Officer's Model length, flush-fit mags...they have the same followers and springs...and the same quirks that sometimes show up with the standard-length Wilson 8-round mags. I won't go into the particulars, but they could use better springs.

Standard Wolff springs won't work with the Wilson-Rogers followers, but I believe that Wolff makes an extra-power spring that will. Contact Wolff for information.

That is all.

Calokie
2nd May 2006, 17:47
Thanks for the help guys. I'll take your recommedations and see where I end up.

Thanks Again

John
3rd May 2006, 01:03
Why are we all such lovers of the +1 magazines? As if one more round in the pistol, will allow us to solve the problem we haven't solved with the previous 6 or 7. God I hate it, but I feel guilty about all those 8-rounders I've collected over the years, still they work OK, LORL :p

1911Tuner
3rd May 2006, 07:28
Why are we all such lovers of the +1 magazines? As if one more round in the pistol, will allow us to solve the problem we haven't solved with the previous 6 or 7. God I hate it, but I feel guilty about all those 8-rounders I've collected over the years, still they work OK, LORL :p

Speak for yourself, bossman. I won't allow'em in the yard. I like for my extractors to last 50-75K. To re-coin one of my favorite phrases: "Just because it's workin' ain't a guarantee that it's workin' right."

The 8-round magazine was born to play IPSC games. They worked pretty well for that, since the practice then was to download the ammo to just make major with 200-grain and lighter bullets...hence reduced recoil dynamics...along with lighter recoil springs and shock buffs...which reduced slide speed and slide to frame impact, and thus reduced the inertial forces, which made the dimple and the full-powered mag springs less critical.
Take a stock pistol and shoot full GI-spec hardball or some of the +P hotrod stuff, and your 8-round magazine is subject to let you down when need for it to work badly...and often does.

There's an old saying amongst people who carry the 1911 for serious purpose:

"The 8-round magazines are like using a .243 for deer hunting. Sooner or later, it'll do less than you need, at a time when you least expect it."

There's a reason that the Marines' MEUSOC
teams don't use 8-round magazines...and you can bet that they tested'em thoroughly before they rejected'em...

I'll leave it to the readers to carefully consider that...