BallisticianX

From what I understand your looking for the pitch of the fine thread on the extension nut so you can remove the extension tube and put a plug in it? If you wish to eliminate the extension tube and just utilize the factory mag tube for hunting it will be easier to just get the factory cap nut replacement. You can buy one here: https://gunrepaircenter.com/vmax-mag-cap-swivel-assb-power-lock/

Out of pure peer pressure I'm building a PCC for some local steel matches. Im doing this on the cheap and with considerable AR parts lying around I'm going the AR-9 route. So first let me overview what I'm working with so you guys can analyze my questions: Lower; a complete Anderson I have for my 300 ACC, POF trigger group, carbine length buffer tube with 5.56 carbine spring & H2 buffer. Will be using a Stern Defense Magwell adapater block to accept M&P0/P320 mags as I don't own a glock but do own an M&P & P320...cut my expense for mags. Upper; 5.56 WMD NiB coated upper, 15" PCF slim hand guard, Faxon 16" barrel and a KAK Industry weighted BCG. (based on my research the KAK BCG seems to be a good choice in the more affordable $100-$125 range. My questions: What combo generally is the best way to go on the recoil setup? What power factor eliminates finicky function between bullet weight changes between 124 to 147? Should I switch to a .308 spring from 5.56? Swap the H2 to an H4/9mm specific buffer?, Leave or remove the BCG weight? My goal, if achievable, is to get this setup to run reliably with a the same powder (most likely WSF as I have tons of it) but with bullet weights ranging from 124's up to 147's, coated or jacketed. Im trying to prevent having to adjust between bullet weights and not beat on the internals either. I'm basically gonna run this thing as the ammo disposal unit and chew up all the different partial boxes of bullets I've accrued over the years while just having carefree fun...hopefully without changing anything. Ive never messed with AR PCC's so I have no idea what works or doesnt. Or how finicky or forgiving they may be. So whatever info/experience you have is appreciated.

Sounds exactly like my experience. Yeah, that Perfecta brass is a scurge as is CBC & IMI. Perfecta always leave a case wall bulge wherever the heel of the bullet ends up when seating. Im glad you found the extractor, I did not, but considering the situation I would have replaced it anyway. I bought the Lone Wolf "Alphawolf" extractor. It works perfectly and tougher than the factory MIM part. My strong advice is to also replace the extractor pin (the part at the end of the extractor spring that has the notch you line up to slide over the rear of the extractor body). That pin is what retains the extractor. In order for the extractor to be blown out of the gun it needs be excessively hinged out and against that pin. With all that force I wont take the chance of a hairline fracture to the pin. Top gun supply has them and they process/ship faster than SIG. I wont lie, this issue paranoid me and put my gun into a "questionable status". Besides the better extractor and new pin I also changed some things to prevent it from happening again. I bought a Faxon barrel that does not chamfer the chamber entry so deep and wide as the factory one for more chamber support, changed to a slower powder (WSF from A#2), and a tad heavier recoil spring (14# from a 13#). Ive put 300 rounds thru it so far and my cases show less deformity near the web and I actually like the way the combo feels better anyhow. As a bonus the Faxon barrel is more accurate than the Sig. At 20 yards its doing 1.5" clustered groups vs the 3" vertical stringing as was the case everytime with the Sig barrel.

I had a case blowout this past saturday with my P320RX of 2019 manufacture that also blew out the extractor. My load (135 gr RMR JFP over 3.8gr A#2) is fairly mild and does not swell the back end of the case like the pics above but they will grow about .002"-.004". Like others said I never had a problem before this. Its a compounded issue of weakened cases and the chamber design. The chamber on the 320's is horribly unsupported and a questionable design in my opinion. It's bad enough so much case is hanging out beyond the chamber face to headspace just below flush with the hood. But they add insult to injury by a "funneled" cut a good 1/8"-3/16" in from the chamber face. Almost like they used a revolver forcing cone cutter to give it a elongated mouth to enhance feeding. The rear 1/3rd of the case is freely able to bloat. Because of this a case that is weakened has the room to fail whereas the same case in a supported chamber most likely would have survived. Im looking into an aftermarket barrel that at least doesn't have that funnel cut nonsense, just a standard chamfer, for a little more support for my own peace of mind.

The case that had a rupture failure for me was marked "P-A RH". I researched it to a company called Precision Ammunition. God knows where the brass was made or what was loaded in it and how many times it was fired before it made its way into my brass bin. Though my cases have never bulged as extreme or as regular as the OP, Ive taken steps to prevent any future issues. I measured and adjusted my COL for .030" clearance from bullet driving band to lands, moved from a 13lb to a 14lb recoil spring, and completely sorted out brass with any off brand headstamp. The case support in these P320 barrels is a point of paranoia for me. The OP's barrel pics show way to much 45 degree chamfer for my liking. My particular barrel does not have near that much but instead it funnels inward, like they used a revolver forcing cone cutter on the 1st 3/16" of the chamber. Both approaches leave too much area for cases to bloat into in my opinion.

The pistol that started out as a P320 RX I won at match. I built it into a poor mans Legion lol. Aggressive stippled TXG grip, modified the OEM slide cut for the RTS2 dot (including recoil bosses), and some simple top and side window cuts. Threw in a GG trigger kit with my mods to the sear for a 2lb-13oz pull. She's classy!

I know this post is a few months old but just stumbled on it researching my similar experience. I have a P320RX of early 2019 manufacture (not the X5 series). FIrst off the pics are of a correctly seated round. The head should be flush to a few thousand lower than the hood. While at a match this past Saturday I had a case failure that bulged identical to yours that also ruptured the case right in the belly of the extractor groove about 3/4 of the way around. Was surprised it ruptured right in the meat of the web as usually a "weak case" breaks open where the case wall meets the web area. Im running a 135 gr. bullet with 3.8gr of A#2 of which is not a stout load. I can also confirm it was not and overcharge as I visually inspect the powder in each case when I manually set the bullet for seating. It just snapped when fired and between the sound and the slide barely moving I thought it was a squib at first. But when I cleared the gun I saw the deformed case freely drop out of the chamber despite my extractor being MIA. No heavy black residue or blown out mag etc, just a missing extractor. I long suspected the healthy clearance at the chamber on this gun was an issue as my spent cases always slightly bloated a bit at the web and this is just more confirmation. My opinion is my situation was compounded by a piece of brass that may have been weakened by previous firings. The unsupported nature of this barrel wont tolerate much in the way of any weakening from cases that have been reloaded even only a few times. Ive also noticed loading to longer COL's that will still pass the plunk test will exhibit more case bulging than if loaded shorter. Seems like the bullet needs a good amount of bullet jump to buffer pressure to make up for the lack of chamber support. Kinda like a 5.56 nato chamber incorporates bullet jump to prevent pressure. I like the P320 but this chamber design and what I've experienced raises doubts for me. I'm looking into an after market barrel in hopes it may have more support. We shall see!

A few variables to case failure rate. Comes down to brand and their quality as companies will use fillers in the brass alloy to cut costs and it results in quicker failure. Then the load and how much it expands the brass. When you form brass it work hardens, or in other words starts to lose ductility. So the more you size the more brittle and uneven the grain structure will become. Now with increased expansion and the greater dimensional correction to resize will accelerate the ductility loss even further. This applies to what mchapman said about case mouth flare. The more you bell that case mouth the more work hardening you induce for a brittle edge. Another caveat is nickel plated brass; that plating tends to compromise the uniformity in the brass when resized as your compressing a non ductile material into a ductile one upsetting the thickness. Ive found nickel plate brass to last only 50% as long as unplated brass in the same situation. As far as brass quality, hands down starline. Ive fired more rounds thru starline without failures than anyone else consistantly from lot to lot.

I would look to another powder vs Titegroup. I never had any luck with Titegroup in 9mm under any coated bullets. Titegroup has its place but 9mm lead loads has not been it for me!. I currently use A#2 in my 9mm lead minor loads. Accurate, clean, cool, and shoots soft. For 135 to 147gr lead WSF is another one that works well (Wsf is cleaner with heavier bullets at minor pf vs the lighter weight bullets). As another poster mentioned Sport pistol seems to be well acclaimed as well, I personally havent tried it yet.

Spot on. Most standard seating dies are A; seating plug off center in relation to the die body, B; seating plug contour doesn't match the bullet profile and wont allow any self centering. The only way to effectively do away with bullet concentricity issues is to use a floating alignment sleeve type die. I have exclusively started using the Hornady Seating dies as they have an effective alignment sleeve design, are cheap, and agree with progressive presses. I had regular problems with Dillon, RCBS, and Lee (hate Lee stuff) seating dies tipping bullets. When I switched to a Hornady floating alignment die I know have zero bullet concentricity issues.

The mouth of the Catskill Creek at the Hudson River is in the Town of Catskill of which is the next Town North of me.

Check the thumb piece, if the screw is not staying tight enough or the portion that sits in the frames recess is worn it could be rotating inducing drag and binding causing your problem. Take the thumb piece off and see if it moves more freely. Take special care when installing the thumb piece to make sure you center it to the frame recess.

The finger lakes region and Seneca is still a good 200 miles from me. I’m in the mid-Hudson valley of N.Y. about 50 miles south of Albany in the foothills of the Catskill mtns. A.K.A the NYC & NJ tourist region. Sent from my iPhone using Tapatalk

Unfortunately your not close or I’d give you some 158 RN berry’s I got kickin around.

I agree with you, all pistols and even revolvers these days come over sprung. Thats why I had ordered a fat guide rod w/15lb spring for easy spring changes before I had the gun in hand. I never actually fired the gun with the stock spring/guide rod in it. Totally forgot about that. I've since settled on the feel of the 13lb with vigorous ejection.

After reading another members post about shooters world "major pistol" and its similarities to A#7 I did a little research as Im an avid #7 user and Ill pass along what I found for the curious among us: Major Pistol a.k.a Lovex D037.1 is made in the Chech Republic by Explosia and A#7 is made in USA (by St. Marks). Seems like no connection, but wait...theres more...Prior to Western Powders purchasing Accurate Arms Company over a decade ago most all the Accurate Powders were Produced by Explosia in the Chech Republic. When Western powder bought Accurate in 2004/05 they severed with Explosia shortly after and contracted with St. Marks (of which was an Olin Company or affiliate) to mimic the Chech made powders for production. So both these powders were modeled after one another and are near the same with the same bulk density but made with different methods so they are very similar but not necesarily interchangeable. So after comparing some older load data on accurate powders with today's Shooters World data it is looking like many of the Shooters world powders may just be the pre-2005 Accurate line up rebranded. With that, one more thing to mention: the bad rap that A#7 had back in the early 2000's about being abrasive, whether true or not, that era's #7 is most likely the same carried on formula your getting from shooters world today as Major Pistol. Whereas todays A#7 is manufactured under a different company. As a bonus to tie it all together one of the Managing Partners of Shooters World used to work for St. Marks.

If the slide is milled on an angle it was, Id guess, done with best intentions based on the sight line to bore line parallelism. ... but not necessary. Ive milled many a slide for direct mini dot mounting (Glock, M&P, SIG, 1911). I always mill the footprint parallel to the slide center line (indicated parallel to the cutters x axis), never been a problem as the sight window is close enough to the bore that the sight and bore planes aren't separated enough to where a sights adjustment will be stressed in any semi on the market. With optic mounts affixed to a frame on a 1911/2011 thats a unique circumstance. Your hoisting the sight window further away from the bore with the 1911's 1 degree pitched down muzzle (slightly more with a shorty). Now your sight plain and bore line are separated more dramatically and both intersecting planes are skewed considerably. Then consider more often than not a fulls size c-more with it taller lens height is used in that application so its even more skewed and sight adjustment range is stressed. So based on that circumstance open gun builders began incorporating the same corresponding 1 degree angle in either the mount itself or with the screw pattern to address that. That's the only hand gun application I can think of where an angle needs to be considered in an optic mount foot print.

3 in/lb of torque is equal to 0.25 ft/lbs. Considering your looking at the 12 in/lb range with a ferrous fastener of which is just "snug" in layman's terms ...other than NASA assemblies or fasteners of #4 and smaller thats an acceptable margin of error without concern.

Nailed it. When I shoot the gun off the bench testing loads I always know when the last round has been striped out of the mag ...the red dot will shift up at the start of the trigger press.

The "cornmeal" is normal in some powders. Most of the Old standby Winchester branded ball powders always did it. You may be right because ball pistol powders in the Western Powder line (Accurate/Ramshot) are manufactured By St. Marks Powders of which manufactured those "cornmealing" winchester ball powders as well. Lastly The one founder of Shooters world worked for St. Marks Powder according to their website. So the ties are there and it very well could be just relabeled Accurate powder from St. Marks or knowing the formula may have his major supplier Lovex duplicate it in Europe.

Sounds like you have a good plan. Do yourself a favor and make sure those 147 TC dont have too much of a flat at the nose. Those 7 flats could be like brakes stopping that clip from dropping if its just out of alignment with the charge holes. For sticking reloads I run RN, nothing better to self center.

Calipers can not adequately measure an inside bore as the jaw flats dont hit the exact crown of the radius. As another said using pin gauges is the correct tool. You can also use an adjustable hole gauge you can set and then measure with a mic. Optimum conditions are the throats to be the same dimension of the bullet and no larger than .001" over, and the bullet sized to seal the guns bore diameter. For example if you have a .357" bore you'll want bullets sized between .357" & .358" for lead/standard plated and .357" for jacketed and any heavy plated. So therefore your throats would be best at .358" to best use a .357 or .358 bullet. Now if your throats are .3565" and your bore remains at .357" than you may be able to get away with a .357 bullet but a .358" will induce leading and possible accuracy degrading. Without slugging your bore Id say find the throat diameters and get the nearest bullet diameter slightly larger and run them and check for accuracy and leading. If it seems fine then be done with it. If its not and you want to remedy it then here's my suggestion. Get yourself a couple hones from brush research and work them to out (youll need a pin gauge to check your progress) I myself open them up to .358" to allow for .358 lead bullets but found no issues with accuracy or velocity when I shoot .357 jacketed thru them.

Crap buildup in this area is normal for revos and lead bullets. But excessive buildup despite regular cleaning is not. The 929 is an interesting beast as its basically made to the same spec as any 38/357 revolver in respect to the cylinder chambers, throats, and bore dimensions. So with a 9mm being stuffed into essentially a 38/357 revolver with a shorter cylinder it posses some further challenges to be problem free IMHO. But here are some general checks to maybe help determine the cause; So depending on which end of the tolerances your dimensions fall on the bullet diameter with lead bullets is crucial in all Smithy's. S&W has a reputation for sending out cylinders with tighter throats than the bore diameter. So if you are sending .358" lead bullets thru a .3565" throat it will buildup lead from the squeeze and each subsequent shot will bulldoze it out and deposit it around the cylinder gap and in the bore. Pin gauges are the tool to check this but in a pinch take a confirmed bullet of .356", .357", and .358" and drop them into a clean cylinder and see what one drops thru the throat easy and what one gives slight resistance or what one needs to be pushed thru with a hammer and punch etc. That will give you a close idea as to where your at. Now with the cylinder gap; the size of your gap determines how much of the deposits blow out between the gap or stay blown into the barrel. Seeing you have an .008" gap which is on the high side of the .004-.010" allowance (.005" is optimum) it will spit more particles and exhibit more buildup on the outside of the barrel to frame area. Its always a good idea to check your timing as well in regards to cylinder to bore alignment. The 929 cylinder is notorious for cylinder wear issues (as apparently you've noticed with your wife's needing a new ratchet/extractor). If the timing is off and the cylinder fails to reach the cylinder stop that would induce a right side favored misalignment. You can usually eyeball the forcing cone area on a dirty revolver and notice abnormal wear and/or visibly uneven deposits in the first 1/8" of the cone ID. Another simple test on a clean revolver is to lay your left thumb against the side of the cylinder (the uninterrupted space between the notches and flutes) with light pressure and stroke the gun slowly with your right hand in double action and watch/listen for the cylinder stop to fall in the cylinder notch before the hammer reaches full stroke and is released. Good luck and hope you get it figured out.

Sometimes a finish reamer is not the best bet. If its close to spec, as yours sounds like it is, a hone may be the better choice. Also the plus side to a hone is they are more forgiving if youve never undertook this before. Using a flex hone, honing oil, and your drill out of the garage you can get it opened up without the worries of over doing it or cutter misalignment as is a concern with a reamer. Honing is a slower process but that allows you more control and less chance for failure. http://www.brushresearch.com/brushes.php?c2=8

Dont overthink it. Not that uncommon to see a 1 grain swing in a batch of bulk bullets. Ive seen more! Just load for 6-7 pf points above the floor based on the advertised weight and you have a built in buffer where a +/- 1 grain variance wont be a concern at chrono. After that as long as the load is accurate your good to go. With typical handgun yardages that 1 grain swing wont be the reason if the the load sucks either. I personally run RMR 147 FMJ that have a 1 grain swing over A#2 in my ICORE revolver and its my money load...nothing has out shot that combo yet!