Cobra magazines sent to me for testing by Virgil Tripp

[1911Tuner]

Since the issue mainly addresses the concerns with 8-round magazines, I'll keep this focused on the 8-round magazines.

First impressions:

Very sturdy construction. Probably the heaviest steel that I've seen in a magazine in some time. Beautifully finished. Slam pads on the 8-rounders is tasteful and not so bulky that they would make concealed carry an issue, though I prefer to use magazines so equipped as spares for the occasions that I carry a fresh reload.

The springs are uber-strong, making loading to capacity something of a chore, but not so bad that it would cause me not to purchase more if 8-round magazines were a requirement. This should rectify itself with a little use, once the springs take an initial set. As expected, locking a topped-of 8 rounder into the gun with the slide in-battery required a bit of force.

The 8-round Tripp Cobras have a little more length in the tube, with the slam-pad covering the extension...allowing more room for a good spring. This is a very good idea. Why nobody else has seen it before now is a little confusing.

Feed lip design is parallel/wadcutter. Interestingly, the release point is later than the typical wadcutter magazines that are on the market. I don't understand what Tripp's reasons are for that, since parallel, early/abrupt release feed lips seem to be at their best when feeding SWC ammo with the typically short OAL used with that type of ammo. Possibly to allow better function recent hollowpoint ammunition that is designed with a hardball-type ogive.

The followers are composite...bearing a resemblance to the Wilson/Rogers design...being constructed of a nylon-like top, with a stamped steel bottom. Also a good idea. and one that addresses the issues inherent to all nylon construction and the chewing up of the slidestop elevator shelf that we've seen with the aforementioned Wilson followers. The followers traversed the length of the tube smoothly and without binding of any sort. They were well matched dimensionally to the tubes' ID and showed no play in either axis.

There's a "speed bump" to keep the last round from jumping the follower...but it's location is a concern. Too far rearward. Should the follower "bounce" a little under inertia during recoil, and the cartridge rim get ahead of it...it may as well not be there. A central location provides the magazine spring more time to get things back under control. The high wpring strength of the Cobra will offset this to a large degree...but as the spring begins to weaken from hard use...the function can easily be compromised. The late release point will also probably work against this jumping of the follower, but at what cost remains to be seen. If the release is timed too late, reliable feed with certain bullet profiles and cartridge overall lengths may be an issue.
We'll see...

Initial testing was limited, and I was only able to run each of five magazines twice. The 6th magazine is in the field, being tested by member Tony Bob in the problematical Smith & Wesson pistol that I worked on a few weeks ago. I'll look up the thread with his findings later on and post the link.

For the initial test, I picked the one pistol in my battery that was most sensitive to magazine function...and the most likely to suffer a magazine-related malfunction. My finest "Frankengun" that I cobbled up from a badly worn 1918 Black Army Colt frame, and a Series 80 Commander top-end. The frame rails and spring tunnel are at stock length, making for a short runup and fast cycle. In this one...if the magazines falter a little...it'll show up sooner or later as a Bolt-Over Base misfeed, or loss of cartridge control resulting in a push-feed return to battery stoppage or loss of tension in the extractor due to climbing over the rim after a push feed...or possibly even a broken extractor claw. It's mostly up to the extractor.

This pistol is equipped with a 16-pound Wolff GM spring, trimmed to 25 full coils, providing an average per spring resistance of just under 17 pounds at full slide travel. A bit oversprung, but I wanted to present the most likely set of mechanics that are encountered on reduced-length pistols...which many manufacturers tend to overspring a little. The "Black Army Commander" was chosen because many manufacturers make this class of pistols with the Government Model rail and spring tunnel dimensions...most notably the Les Baer Stinger...ignoring Colt's specs for their very successful Commander line. Why this exists remains a mystery.

I fired 80 rounds of mixed ammunition, evenly split between reloaded 230 FMJRN at standard hardball velocity and an OAL of 1.260 inch...to the homemade 200-grain SWC cast in the RCBS 201-grain mould that is essentially a slightly modified H&G #68. OAL was 1.240 inch.
Velocity is in the 870 fps range for the SWC ammo. Not hot-rod stuff, but qwuite a bit hotter than typical SWC bullseye-class ammunition.

Function was flawless, with no feed or return to battery occurrences, though chambering the top round provided a little more "ka-chunk" than I like, when placed into battery from slidelock using the slidestop to trip the slide. This isn't present with this pistol with the Metalform SWC magazines...72 of them...that make up my range-only group. Since the only basic difference between the two designs is the later release point of the Cobras...I have to attribute it to that. Oddly enough, the longer "hardball" ammo provided slightly smoother top-round chambering than the shorter SWC. The chunky "feel" disappeared with both types of ammunition on the thrid round in, and all was smooth from that point. It might be worth mentioning...and I hope that I can without evoking a flame war...that the tapered lips of the Check-Mate "Hybrid" magazines...produced smooth feed on all rounds in this pistol. The same goes for the full-tapered USGI WW1 and WW2 contract magazines...with both ammunition types.

Note that the feed ramp in this frame is untouched and unaltered. The only polishing that has been done is through use, and the only "tweak" that it's undergone is the slight lowering of the frame bed to obtain sufficient barrel drop clearance after peening the rails. This pistol proved to be a little problematical at first when fired with anything except hardball until I set the barrel ramp slightly forward, taking the standard prerequisite 32nd-inch gap out to about .040 inch.
Any less, and the bullet noses were striking the center of the barrel ramp, causing light 3-Point jams. Once done, the gun has fed almost flawlessly from 7-round magazines equipped with Wolff springs...no matter what the feed lip design. Metalform's standard springs weren't up to the task, and I was getting frequent bolt-over base misfeeds on the last round until I upgraded the springs. I still get an occasional stoppage when using the 200-grain SWC ammo...about once in 500 rounds on average...and zero stoppages when firing hardball or RN cast since the spring upgrade.

In the coming week, I'll test the magazines again with pistols separated in groups of five.
I hope to get started tomorrow, weather permitting. I'll also try to get a couple of the magazines in the hands of Beta testers with guns of various manufacure in order to get a better overview of the performance in the typical off-the-shelf pistol.

In order to prevent too much clutter on this thread, I'll ask that everyone posts their Q&A in this thread: http://forum.m1911.org/showthread.php?t=47439

[1911Tuner]

For the first phase , I selected four Colts that have been so functionally reliable that it's almost absurd. All are high-mileage guns, and all have been rebuilt and refitted, and fitted with Kart barrels. Although the guns are rattle-free, they're not fitted as tightly as a custom or semi-custom, and have been set up for reliability a first requirement. Two are early 1991A1s and one is a mid-production 1991A1. The fourth is a NRM 01991 Government Model producted in late Y2K.

These pistols were selected because of their absolute reliability with 7-round magazines... regardless of feed lip design...in order to establish a baseline. The usual "range load" consists of 72 Metalforms with parallel/wadcutter feed lips and Wolff 11-pound springs. All four pistols were thoroughly cleaned and oiled prior to the first run. As the testsing progresses, I'll dirty them up and retest them in order to get a comparison.

The ammunition for this phase will consist of home cast 200-grain H&G #68 clones, loaded with 6 grains of Unique for an estimated velocity of 870 fps. Cartridge OAL is 1.245 inch.

For the first run, I'll fire all five magazines in each pistol in rapid succession, with notations made. Any that fail will be retested in the gun that suffered the failure. If another failure occurs, that magazine will be tested in the other three guns, under the same conditions in order to rule out a particular gun's preference for a particular magazine...and the magazine will be marked for identification. If the failure isn't repeated in 10 attempts, it will be returned to the group without identification.

The first phase begins in approximately one hour. I'll try to get it written up and posted by this afternoon.

[1911Tuner]

For clarity, the trio of 1991A1pistols involved will be identified by the last three digits of their respective serial numbers, with the NRM Colt as simply NRM. "New Roll Marked" for those who aren't aware of the difference. Aside from the smaller rollmarks and polished flats on the slide...the guns are identical.

Feeding with the SWC ammunition was good. #187 experienced a failure to feed on the third round which...although I couldn't reproduce it in 10 attempts...fed a little less positively for the first 3 rounds. Once I got past that point, feeding was smooth and solid. The glitch was isolated to one magazine.

Slidelock on empty was flawless for all magazines. Two of the magazines wouldn't drop free from the magwell on any of the pistols. A minor nuisance that's likely a matter of tolerance variations, and easy to correct with a light squeeze in a mill vise. It might be worth noting at this point that I don't consider that issue to be a malfunction. A matter of fine-tuning at worst.
All manufacturers will have this happen with a certain percentage of their magazines. None are immune.

Even though the magazines had been loaded to capacity and left for 72 hours prior to the test, they were still a bit tough to work the top two rounds into.
Another small nuisance, but one worth noting for those of us who like to fire several hundred rounds per session, and can only justify a half-dozen magazines. Loading my normal 72 Metalforms with Wolff 11-pound springs doesn't leave me with sore thumbs like loading the Cobras 15 times. Note that I don't have tender thumbs or weak hands. A magazine tool is probably a requirement for high round count sessions.

Pistol #103 experienced a light "ka-chunk" feed on the top round from slidelock, whether chambered via the slingshot or the slidestop trip method.
This was noted on all magazines tested. No failures to go to battery resulted, though light damage to the bullet nose was observed. Bear in mind that I've become used to these pistols feeding so smoothly that someone who wasn't familiar with them would doubt if they'd stripped a round at all.
Several have doubted it, in fact. Again...not a major problem, since the gun didn't fail to go to battery. I have a suspicion that this probably has more to do with the late release timing than anything else.

Overall, a pretty impressive performance, though I might remind the readers that these pistols are so boringly reliable that I never get to practice malfunction drills unless I purposely induce one. Today's test was to establish a baseline only, and to set a standard.

The next group will consist of four USGI pistols that are basically stock, except for the 1942 Colt that has been tightened and refitted, with a Kart barrel installed during the overhaul. I hope to do this one Thursday or Friday.

[1911Tuner]

To bump this back up top, and to outline the next group of pistols to be tested...probably Thursday, barring unforseen circumstances.

I'll split this up into two parts, since I've been limited as to the number of characters that I can use per post. This is only to identify the players.

The pistols:

One each, 1942 and 1943 USGI Colts. Both guns have been peened/refitted, with Kart barrels installed and fitted to minimum ordnance specs. No polishing or alteration has been done to the feed ramps. The barrel ramps are as delivered from Kart. Both pistols have been boringly reliable in feeding hardball or the 200-grain LSWC ammunition, as long as the magazines are full-tapered or tapered/timed "Hybrid" type 7-round magazines. Parallel-lipped 7-round "wadcutter" magazines are reliable in these pistols with hardball...Winchester 230 hollowpoints...and Remington 230 Golden Saber. Of the two, the 1942 is the more reliable with SWC, using wadcutter magazines...though still a little balky when it gets dirty.

The '43 will feed 200-grain SWC from the 7-round Metalform wadcutter magazines with about a 75% certainty. If the Cobras with their high presentation angle are superior to standard parallel-lipped "wadcutter" magazines...these two pistols will prove it.

These two Colts do yeoman service as carry guns on a regular basis. I trust them that much.

A mint 1945 Remington Rand...unaltered, bone stock, and original. It will function reliably with 200-grain LSWC ammunition from 7-round "Hybrid" magazines and GI magazines that have been tweaked for SWC ammo. Hardball, of course is a sure bet, as are the two aforementioned hollowpoint rounds. Wadcutter magazines are "iffy" with anything except hardball. This pistol has seen only limited use with any ammunition. Hey! It's valuable!
I had to twist my own arm to even include it in the tests.

An original, VGC 1919 Black Army Colt. Feed reliability with various ammunition styles is a match for the Rand, if a bit moreso with LSWC and tapered magazines. I can get the Rand to hang one up occasionally by hand cycling. The old Colt has never missed.

I tossed in an original, but refinished 1925 Colt Commercial Government Model in excellent mechanical condition at the last minute. Best educated guess is that this gun has probably seen no more than 500 rounds, and...other than the botched reblue effort...it's the best example of a stock, pre-war Colt that I own. Another one that can't tell the difference between hardball and SWC and 230 hollowpoints, as well as Hornady's excellent 230-grain FMJFP...or "Truncated Cone" bullet, provided the right magazines are used. I've never tried this one with wadcutter magazines...so it should prove interesting. If it chokes on the Cobras, I'll do a short retest with a few of the Metalform range beaters in order to determine any difference.

[1911Tuner]

The ammunition:

201-grain LSWC RCBS mould w/1.245 OAL
230-grain LRN RCBS mould w/1.235 OAL
225 grain LRN Lyman mould w/1.260 OAL
230 grain hardball Winchester bullets w/1.260 OAL

At the last moment, a friend decided to join me and we also tested his mid-production 1991A1 Colt with several of his handloads, including 200 and 230-grain Hornady XTP hollowpoints.

The 1942 Colt was first up. Feeding with the 201 LSWCs was stellar, with zero failures. Likewise with the 230-grain RCBS LRN with the short OAL. Feeding became a little less smooth with the longer 225 grain Lyman LRNs and the hardball...though there were no failures. Again, I feel that this is due at least in part to the late release point of the Cobra mags.

The 1943 didn't fare as well with the SWCs, producing three failures to return to battery...each time on the last round. Two of the failures refused to go to battery by hitting the slide, with one slipping in easily with just a nudge. The two magazines were retested under the same conditions...and the failures repeated. All RN ammo fed without a hitch, though...oddly enough...the short OAL with the RCBS bullets gave up a pronounced "Ka-Chunk" feed on the top rounds from slidelock...regardless of the method of release. After the top rounds, all was smooth.

Third in line was the 1919 Colt. The pistol consistently failed to feed and go to battery with the LSWC ammo. Retesting with the pair of original USGI magazines proved that the ammo was good, as the pistol went through 2 magazines without a hitch. The longer RM ammo fed smoothly from the Cobras, but the shorter RCBS again was a little problematical with hard feeding on the top round which disappeared once the top round was chambered. There were two failures with this ammunition...which chambered with a light bump on the rear of the slide.

The Remington Rand also failed with the LSWC ammo...and again proved that the ammunition was good with a Check-Mate "Hybrid" lipped mag and a WW2-era Scovill USGI hardball magazine. All RN ammo fed without failure, and all were equally smooth and positive in the Rand.

The Commercial Government Model was the star of the show, with only one failure with the SWC ammo that didn't repeat in three retests.

Due to the collectible value of the latter two, only two magazines per ammo type were fired per gun. Four magazines per ammo type were fired in the rebuilt Colts and the Commercial Government Model.

Robert's 1991A1 also ran well with the Cobras. He fired several hundred rounds through the gun with various ammunition with no failures. His pistol has been a "chunky" feeder with 230 hardball from parallel-lipped SWC magazines on all rounds...most notably the top round from slidelock...and his observation was that the feed was noticeably smoother from the Cobras when using his hardball equivalent handloads at 1.260 OAL. The rough feed in his pistol often produced the "Pogo Stick" effect that many notice when a shock buff is shredding and tying up the slide. This comes from the bullet nose hesitating on the feed ramp before going to battery...usually as the pistol gets dirty and fired hot. He said that it never happened with the Cobras, and that it ran smoothly from the time he started until he ran out of ammo.

There were no failures to lock the slide on empty. There were two instances of failure to drop free in the rebuilt USGI Colts...each time with the same magazine. Again...just a matter of tolerance stacks that's easily rectified, and essentially a non-issue as far as I'm concerned.

There was one failure to drop from the Remington Rand with a different magazine than it occurred with in the Colts. The 1919 Colt, the Commercial Government Model, and the 1991A1 all squirted the magazines out of the magwells.

Next week..."The Chinese Connection" which will consist of a half-dozen 5-inch Norinco pistols.

In order to prevent too much clutter on this thread, I'll ask that everyone posts their Q&A in this thread: http://forum.m1911.org/showthread.php?t=47439

[1911Tuner]

The six Norincos to be used in this phase vary from lightly tweaked for reliability to one that's dead stock, loaned to me by a friend. Other than that one...all pistols have been refitted with Kart barrels. Two have been radically peened to lower the slides to correct excessive vertical specs, and the other three have had the rails swaged to eliminate excessive vertical play only.

One of the pistols was refitted much more tightly than my normal rebuilds. Not Bullseye class...but tighter than my usual habit of going with minimum ordnance clearances. Yes. I fit the barrels tightly...shoot to settle everything in...and then go back and loosen them up a bit.
This one is wicked accurate with my SWC handloads, though it tends to be a little finicky as it gets dirty...normally within 200 rounds of the lead bullets, and about 500 jacketed rounds. That's to be expected for a pistol this tight.

One of the guns was a resurrected basket case that had been burned up in a fire. It required pretty extensive massaging, but has proven to be accurate and reliable enough to carry...and that's saying something. All the pistols in the test have been reliable from 7-round magazines, with the smoother feeding provided of course by the tapered hybrid or full USGI hardball designs. The stocker is unknown to me, but its owner swears by it when fed hardball and Winchester 230-grain hollowpoints. He's never fired it with SWC...so this will be new ground for it.

No frame ramps have been polished beyond light tool mark burnishing. All barrel beds have been lowered by varying amounts, with the ones requiring rail peening/lowering undergoing the most for adequate barrel drop clearance.

A friend was good enough to loan me his RCBS 200-grain SWC mould. It drops a bullet with a shorter, stubbier nose than my RCBS 201-grain #68 clone. I'll cut a couple hundred of the bullets today or tomorrow and have them loaded into brass by test day...which looks like Tuesday, weather permitting and a dog doesn't get sick.

Ammunition for this phase is:


201-grain LSWC RCBS mould w/1.245 OAL
230-grain LRN RCBS mould w/1.235 OAL
225 grain LRN Lyman mould w/1.260 OAL
230 grain hardball Winchester bullets w/1.260 OAL
200-grain LSWC RCBS mould w/1.200 OAL

This will be the most extensive test thus far, and I plan to run 800 rounds through the six pistols...or possibly more. I hope to have it all done in one day, but I may have to split it up over two days. If that turns out to be the case, I'll do my best to make the days consecutive.

If it turns out that I have to make it a two-day test, I'll probably include some factory ball ammunition...likely Mag-Tech, since that's what I have a goodly supply of and don't mind using. (Hangin' onto the PMC) I'd very much like to test a good bit of hollowpoint, but it's getting to be fairly scarce around here, and prohibitively expensive. I may break out some of the Hornady 200 and 230-grain XTPs that I loaded up about 10 years ago.
For the record...The XTPs are a truncated cone design, and have caused problems in a few untweaked pistols over the years when the OAL is longer than 1.235 inch. Mine are set at 1.220 for the 230s, and 1.200 for the 200s as per Hornady's recommendation. At that length, they're much more reliable in the average off-the-rack pistol.

Stand by...

[1911Tuner]

Due to time limitations, I was only able to run each of four magazines through the six Norincos three times...for a total of 576 rounds/96 rounds per pistol. I'm down to four magazines after sending one to Hunter to evaluate in a Colt 1991A1 that's been giving him trouble with other 8-round magazines.
I've asked him to report his results on this thread.

I used 4 magazines each of hardball at 1.260 inch OAL...4 each of the RCBS 2310 at .1245 inch OAL...and 4 each of the "snub-nosed" 200-grain LSWC at 1.190 inch OAL.

All pistols ran well with hardball, which was expected. Two produced a light "ka-chunk" on the top round from slidelock...also expected because of previous experience with wadcutter-type magazines and hardball in those pistols. The others were smooth and sure.

When I moved to the RCBS 201-grain LSWC, things started to get interesting. The ka-chunk feed on the top round was more pronounced in three of the pistols, but the issue was lessened on the next round. By the third round, it was gone, and the guns fed smoothly.

The bone stock pistol adamantly refused to feed the top two rounds from all 4 magazines, producing a hard 3-Point Jam with every attempt, and the only way that I could get the top round in was to chamber it from the OEM magazine, and fire 7 from the Cobras.

It might be worth noting here that, typical of Norincos...the barrel didn't have the prerequisite
32nd-inch gap between the bottom of the barrel ramp and the top of the feed ramp...sitting dead flush with the barrel held back against the vertical impact surface. So, the problem was mostly with the gun.

When I moved on to the more stubby 200-grain ammo...and the Cobras were suddenly in their element, with all pistols feeding dead smooth except the stocker. It still gave a problem with the top two rounds, though it did go to full battery with 3 our of four magazines. The one failure required a light bump on the back of the slide in order to chamber the round. My suspicions about the late release point and cartrdge OAL of more than about 1.210 were starting to prove.
A quick retest of the ammunition in the 7-round Metalform magazines with an earlier releast point bore this out, as the guns fed and went to battery...albeit not as smoothly as I'd like in two pistols.

All magazines dropped free in all pistols tested. There were no failures to lock on empty.
I'd left the magazines loaded to capacity since the last test to see if they'd take further set and reduce some of the difficulty in loading the top round. It didn't work. These are some throwdown good-quality springs, and I don't forsee any premature weakening with heavy use.

I have one further Norinco test to run, and it'll probably be with the next group.

Next up: The Commanders.

[1911Tuner]

Bump, and to let everybody know that, if all goes as planned...I'll be shooting the Commanders on Sunday morning. If not Sunday, then it'll have to be Thursday, the 3rd of April.

For the test, I'll use 18-pound recoil springs in the pistlos because that's pretty much the accepted "standard" nowadays. Any that give problems will be retested with my trimmed 16-pound GM springs. Thanks to Bob Allen for the loan of the new Wilson Commander-packaged 18-pound springs.

[1911Tuner]

Rain off and on today. Looks like it'll be Thursday.

[1911Tuner]

Bump. Weather and a very sick Collie forced me to stay at home today. I'll try to get this next one in motion by Monday or Tuesday.

If I lose this dog, I may not be in shape to do anything for a week or two. I cut and tied his umbilical cord the day he was born and sat up with him the first night to keep him breathing...and he's been with me for nearly 8 years...so this one's gonna take a lot out of me if he goes.