Do all Semi drop In barrels have a "Government" shaped barrel knee profile which make the pin ride the link?
From various manufactures that is and like this profile:
The only one I've got at the moment is an inexpensive Auto Ordnance and it matches the one in your pic. With a 278 link, the pin touches the feet only in battery and that contact is at the aft surface of the pin. A true link rider.
I believe 1911Tuner has posted that a military M1911 or M1911A1 typically rides the link. There's simply too much delicate work involved in fitting a barrel to ride the lug for it to be practical in mass production.
I am just trying to plan the step for my MetroArms update-learning-fixing- playing-shooting 45ACP. Perhaps a NM barrel will be my next project. (I know it already has one) I wanted to understand exactly what "semi-drop-in" means when I review the barrel selection available. I will need at minimum, listed below, to fit a NM barrel:
1. Brownells lug cutters (can be used on most NM top end barrels)
2. No Kart easy-fit (probably will not be selected because of it's limited "teach-ability")
3. Brownells barrel locking lug file.
4. Depth micrometer (not calipers)
3. Dyechem blue to determine surface contact.
Just planning... no "semi-drop-in" barrels will be considered for this project.
There is a difference between a "match grade" barrel (which everyone claims to sell these days, and an NM (National Match) barrel. Your Metro Arms does not likely have an NM barrel.
Perhaps some wishful thinking about the Metroarms Barrel. I drew the conclusion the Metroarms has a match grade barrel because the Metroarms barrel lower locking lugs (knees) have the much different caming profile than the drop-in Colt barrel (government barrel). The hood is also very tight compared to the Colt drop-in.
I have no experience about 1911 barrel replacements other than what I have read and the one Colt government barrel I put in my Metoarms.
I want to understand the difference between:
1. Drop-in barrels from any manufacture.
2. Kart easy-fit barrels.
3. Bar-sto match barrels.
4. Schuemann match Barrels.
Right now I can't get away from the history and lure of names like "Bar-Sto" and "Schueman" over Kart. I know that the Kart will probably be easier to fit like the name implies but I just am in a state of indecision.
I'm curious as to why you want to replace the barrel on a new pistol. A new barrel from a "name" manufacturer is going to cost you half the price of the gun, and then you have to fit it. What do you expect to gain? Can you shoot well enough to perceive the difference in your targets?
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I'm curious as to why you want to replace the barrel on a new pistol. A new
barrel from a "name" manufacturer is going to cost you half the price of the
gun, and then you have to fit it. What do you expect to gain? Can you shoot
well enough to perceive the difference in your targets?
Experience is the only thing that I want to gain. Plus a better shooter.
I couldn't even find a used beater 45 for the price of the Metroarms NIB to start working on to gain this experience.
Another one of my goals is to get the Metroarms to shoot as good as my TRP Operator. When/if I occomplish this then I will sell the TRP for hopefully more money then I have spent on the MetroArms.
TRP Operator cost me $1200 (I think they are more $ now for a railed TRP with bull barrel and adjustable sights). The Metroarm cost me $475 out the door so I have about $700 difference between the two.
The TRP is very accurate and dependable, except for a recent trigger issue that is being repaired under warranty, and I hope that I can make the MetroArms just as accurate and dependable.
Hopefully I only need to replace the barrel and trigger group to acheive this ($210 Kart easy-fit barrel + $140 Cylinder & Slide trigger group = $350; $350 + $475 = $825 winner )
If she shoots well then I may even add an utility rail for my night light. Oh, and home Parkerize. For some reason polished/shiny blue isn't durable enough for my tastes.
Here's a pic of that inexpensive AO replacement barrel previously mentioned:
The AO parts list just called it "barrel" and it dropped in without any fiddling, so I guess you could call it a "Drop-In" - because it did. And just by eyeballing, it's lower lug profile looks like a dead ringer for the most recent Ordnance Gov't Issue barrel shown in the blueprints from Nicolaus Associates. That's the basis for the 20 Sep 09 drawing in your pic. Earlier Ordnance blueprints for the Gov't Issue barrel are slightly different in the lower lug area, but those barrels ride a 278 link too.
The only barrels I consider true NM (National Match) barrels are those manufactured by either Colt or H&R for the Army during the middle 1960's. Their part number (7791414) is stamped above the chamber and all those barrels were manufactured according to Ordnance drawing number 7791414.
However, it may be safe to asssume that any barrel claimed to be a NM barrel probably meets at least the exterior dimensional specs as long as the muzzle area's a bit bigger and the hood and lower lugs are oversized and require fitting. J.K., Vol II, page 189 has some (but not all) of the NM barrel dimensions.
Then, as you said, there's the "Match Grade" category - which is probably any barrel not in the Gov't Issue or NM category. To me, "Match Grade" has about as much meaning as "Tactical". There's probably somebody peddling "Match Grade Tactical Titanium Thumb Safety Plungers" at this very moment!
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Then, as you said, there's the "Match Grade" category - which is probably
any barrel not in the Gov't Issue or NM category. To me, "Match Grade" has
about as much meaning as "Tactical". There's probably somebody peddling "Match
Grade Tactical Thumb Safety Plungers" at this very moment!
Thank you for the clarification... now I know everyone monopolizes the name "match Grade" for there own gains. I really am interested in hand fitting an oversized lug/hood barrel. I will refer to these type barrels as "oversized" rather than "match grade" from now on.
Perhaps I can stamp the words "Eric's Tactical" on the slide in big letters before I refinish the pistol because Springfield does consider their gun a "Tactical Response Pistol" My will be made directly on my tactical workbench.
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I really am interested in hand fitting an oversized lug/hood barrel. I will
refer to these type barrels as "oversized" rather than "match grade" from now
on.
If the lower lugs and hood are oversized it wouldn't be too much of a stretch to call it a NM barrel either - even though there are other differences.
This NM barrel business gets a bit complicated because there are actually four different (different part numbered) Ordnance Dep't barrels designated as NM ones! Good info about them in the April 1963 and July 1966 issues of The American Rifleman, but no dimensional data for the lower lugs.
Doesn't the NM normally require a longer link? If so, why?
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Doesn't the NM normally require a longer link? If so, why?
Yes, and here's why.
A Gov't Model barrel with a 278 link is supported vertically in battery by the link. There will be about 0.040" of vertical locking lug engagement and the link will hold the lower lugs almost 0.010" off the slide stop pin.
When a NM barrel is fitted, the oversized lower lugs are cut so that the slide stop pin supports the barrel vertically in battery with a maximum vertical locking lug engagement of almost 0.060" - perhaps 0.020" more than the Gov't Model.
All this means the barrel bore axis (and link pin hole in the barrel) can be as much as much as 0.020" higher up - and a longer link is required. My hard- fit NM barrel has about 0.056" of vertical engagement and requires a +17 link.
Now we are into some meat... and if you don't mind me asking...
Is that NM barrel an oversized aftermarket brand name or one manufactured by either Colt or H&R for the Army during the middle 1960's to Ordnance drawing number 7791414?
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Is that NM barrel an oversized aftermarket brand name or one manufactured
by either Colt or H&R for the Army during the middle 1960's to Ordnance
drawing number 7791414?
It's one of the ones made by H&R for the Army in about 1965. That drawing/part number's stamped right on it. Got it with a NM bushing in about 1966 from a 'smith outside Bangor, Maine for US$10, IIRC!
I think they were made available to civilian shooters & 'smiths through the DCM.
Hi niemi24s, I understand the NM barrel fitted with 0.060" (max) locking lug engagment, supported by the barrel feet cut to lock up on the slide stop pin... this is the way I believe most custom gunsmith fit barrels are done. I am surprised that barrels are fit "link bound" to force the barrel into the locking lugs even on production run guns. Wouldn't this limit the useful life of the pistol? Certainly of the link and the link pin? I guess you could sell me that bridge in the Florida Everglades also?
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I am surprised that barrels are fit "link bound" to force the barrel into
the locking lugs even on production run guns. Wouldn't this limit the useful
life of the pistol? Certainly of the link and the link pin?
There's no doubt some additional stress on the link & link pin in a link- riding Gov't Model, but I've no idea how long it would take for that additional stress to wear out a link or link pin. Maybe 50,000 rounds?
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There's no doubt some additional stress on the link & link pin in a link-
riding Gov't Model, but I've no idea how long it would take for that
additional stress to wear out a link or link pin. Maybe 50,000 rounds?
However many rounds it takes ... my Colt 9mm Commander went well beyond it before I got it. I bought the pistol used, and when I stripped it the pin simply fell out. Even a so-called "oversized" pin (which is really just a pin manufactured to the maximum spec) from Brownells falls out every time I field strip the pistol, and the holes in the barrel lug are slightly egg-shaped.
Curiously enough (or not?), the pistol still shoots and functions just fine.
This is very interesting... perhaps something like this barrel from GB might be in order... although it must already have been fit to something before.
IIRC, there were also some NM barrels made by IMI in recent years.
Also, FWIW, here's a link to some of the NM info mentioned in Post #11: http://www.coolgunsite.com/images/1...match_notes.htm
Very interesting... an unfit NM would be really nice... especially if I fitted it to a Colt.....but I can't bring myself to consider and old NM a legitimate barrel replacement for my MetroArms...
I will decide whether I want to buy a $180 lug cutter from Brownells and a $200 Bar-Sto barrel
or
$160 Kart easy fit barrel and $44 fitting kit. (The $180 difference makes me want the Kart)
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...I can't bring myself to consider and old NM a legitimate barrel
replacement for my MetroArms
Good decision. That number on the side of the barrel in your pic is the serial number of the gun in which it was originally fitted.
Having been previously fitted, there may not be enough material left on its hood & lower lugs for a proper fitting in your gun.