Cast boolits in M&P 9mm Pro?

[prickett]

I've been fighting accuracy problems with my M&P Pro (9mm) for some time now. Recently I spent a considerable amount of time cleaning out leading. I'm casting 124 gr Lee boolits using a 3:1 ration of COWW and range lead. I size to .358" and coat with Hi-TEK.

I've also purchased commercial lead boolits from Dardas, also sized .358" and seem to be getting leading/poor accuracy from those too. These work very well in my CZ, but not in the M&P.

Does the M&P have an unusually large inner diameter barrel? Are any of you shooting lead from the M&P? And if so, what diameter are you sizing to? Are you getting any accuracy out of them?

TIA

[wcp4570]

My son has 2 Pro's and 1 L model that he and his 2 oldest kids shoot. They shoot the Lee 120tc sized to .357 with no problem. He was experiencing leading at first until we got the .357 size die. Boolits are cast from COWW, water dropped and lubed with BAC. My boolits have been shot in another Pro owner that shoots steel with my son. I also shoot the same boolit in 4 older S&W models with no problems. You should slug your barrel to ensure your boolits are sized +.001 over bore diameter.

wcp

[upnorthwis]

I'm shooting that same boolit in my M&P and had the same problem. Was loading them on a Dillon 550B and tried one in the cartridge gage and it wouldn't fit. So I took the taper crimp down until it did. Problem was that I was putting too much taper crimp on them and was crushing the boolit undersize. Should have done the "Plunk test" as all of the range brass I pick up is fired in unknown chambers.

[mdi]

9mm can be a headache to shoot lead bullets in. Properly coated Hi-Tek bullets should not leave leading, that's the benefit of coating. I've had some leave a kind of fouling, but no lead. Perhaps as upnorthwis mentioned, too much crimp. Could be cutting through the coating and exposing raw lead along with swaging. I would try plain WW alloy as this has been the "go to" hardness for all my cast bullet shooting from .38 wadcutters to .44 magnum, and an occasional 7.62x54 batch. Slugging, knowing for sure, the groove diameter is very important. I'd back off the crimp so the cartridge just passes the plunk test (I don't crimp any of my 45 ACP nor 9mm ammo, I just straighten out the case mouth with a taper crimp die.) go with pure WW, and try a different lube (Carnauba Red has worked for me in 9mm)...

Jes a thought, and more info can be found in Coatings and Alternatives, perhaps the coated bullets are too large and "cutting" through the coating? Do you size to .358" after coating? Have you slugged the gun's barrel, it may be .355"...

[osteodoc08]

There were accuracy issues with some of the M&P 9's due to barrel to slide lock up. It's well documented over on the smith forums.

Before chasing that down, how do they shoot with regular J-Werds? Have you tried slugging your barrel or shooting a larger boolit to rule out it problems?

[zomby woof]

Are you using a LEE FCD? I run mine .357, no need for .358 in mine. Might need a harder boolit. Is the 124 a TL design?

[prickett]

Some additional info:

Not using Lee FCD
Not the TL design - conventional design
Commercial lead was ordered with a .358" sizing. Measuring looks like it is actually .3577"
Haven't tried jacketed. Am going to do so this weekend.
Suspect that maybe too much crimp/too little belling resulting in boolit being squished (is swaged the correct term?). Will pull a few tomorrow to see.
Not certain whether it was the commercial lead or my own cast/coated boolits or both responsible for leading/lack of accuracy. Need to bench the pistol and only shoot one or the other.
Haven't bothered to slugged the barrel since I'm running .358" boolits. Not sure what slugging would tell me. I've slugged my other barrels, found they were all over the place, and opted to run the largest diameter that would function - so I wouldn't have to size per gun. Is that logical? Or, am I missing something?

TIA

[Houndog]

I have 3 M&P 9MM and use the Lee 124gr conventional lube groove boolet in all of them. I use wheelweights plus 2% tin, water dropped, sized to .357 and lubed with White Label BAC. I use 5gr Unique and load to 1.050 length. I don't even get a hint of leading I know other board members will disagree, but I think your boolets are too soft. If you decide to try my recipe you do so at your own risk!

[Lloyd Smale]

most semi auto pistols do better with harder lead. I use either water dropped ww or #2 in mine. Also size them as big as your gun will reliably shoot them. If you haven't already done it, shoot about a 100 jacketed bullets through your gun to smoothen out any rough spots in the rifling. If that helps but it still isn't up to your standards try fire lapping the barrel. I'm not a pro on coating bullets. Ive done a little and its worked pretty good for me but Id also consider trying conventionally lube sized bullets with a good soft lube.

[Landshark9025]

I had issues with leading in my HK. Granted, that was a polygonal rifling. It wasn't bad, but certainly not acceptable. I was sizing them to .357. Tried .358 and it got significantly worse. What solved it was .357 and harder alloy.

Go ahead and slug your barrel. If it turns out it is .3555 or even .356, I'd try bullets sized at .357 and a harder alloy.

[bilco]

Having leading issues as well in my m&p9L and this is with Hi-Tek coated bayou bullets- I pulled a couple of loaded ones and there was no over crimping into the lead so I am not sure what the deal is. I also am not sold on the Hi-Tek coating either. It seems way to damn finicky/fickle to get correct and I am starting to wish i never spent the 80 bucks on the stuff.

Related to the m&p leading: mother of god is it a pain in the **** to get the lead out of this barrel. My 1911 barrels are a joy to get leading out of compared to this thing. Anyone have any suggestions other than tightly binding up some chore boy on a brass jig and ramming it through for deleading?

[Cherokee]

I have found in my 9mm guns (XDm's & 1911's) that a harder alloy gives me more accuracy w/o leading. I use .356 in my loads. I did find that less taper crimp was better, just straighten out the case mouth.

[prickett]

Having leading issues as well in my m&p9L and this is with Hi-Tek coated bayou bullets- I pulled a couple of loaded ones and there was no over crimping into the lead so I am not sure what the deal is. I also am not sold on the Hi-Tek coating either. It seems way to damn finicky/fickle to get correct and I am starting to wish i never spent the 80 bucks on the stuff.

Related to the m&p leading: mother of god is it a pain in the **** to get the lead out of this barrel. My 1911 barrels are a joy to get leading out of compared to this thing. Anyone have any suggestions other than tightly binding up some chore boy on a brass jig and ramming it through for deleading?

I have an Outers Foul Out 3. Unfortunately they ceased making this. But its been a life saver. You stick a metal rod in the barrel along with a solution (whose formula is available online). Every few hours you simply wipe the accumulated detached lead off the rod, then reinsert. Several iterations later, it comes out sparkling clean.

Look around to see if you can either find a used one or a homemade version.

[prickett]

Has anyone had success with plated boolits in an M&P? I've heard a lot of complains about keyholing with plated. I assume it is due to .355" boolits being shot from .357" or .358" barrels, but am only guessing.

[Lloyd Smale]

I shot about a 100 120 roundflats sized to 358 and coated with smokes black. Didn't lead a bit. Good accuracy and no sign of tumbling. They say though that coated bullets are a bit slower then conventionaly lubed bullets so if your loading on the light side you might be slow enough that there not stabilizing.