.45 acp and polygonal rifling.........

[3006guns]

I'm looking at several of the "compact" .45 acp's right now, and at least one has polygonal rifling. I've never owned a handgun with this form of rifling and I'm curious as to what effect it might have on cast lead boolits.....


Anyone have experience, good or bad, with this?

[hockeynick39]

Read the Glock thread, should have all the information you need to know about polygonal rifling. One of the first things I did when I picked up my wife's new Glock 43 was to take out the stock barrel and throw it in the trash. I then put a Double Diamond barrel in and haven't looked backed. The wife doesn't even know the difference!!!!!!

[johniv]

I have an H&K USP and shoot my own cast in it. No issues at all. I have never tried commercial cast. I size to ,4525 and get no leading at all.
FWIW
John

[EMC45]

I shoot cast exclusively in my Glock G36 with FACTORY barrel. I have found that Glocks shoot just fine with lead ammo. Shot my buddy's G43 over the weekend with .356 and .358 bullets and the .358 did way better and were more accurate. Bullet fitment is key no matter what type of rifling. I have shot .40, 10MM, .45 and 9MM Glocks all with FACTORY barrels and lead bullets and they all did just fine.

[DougGuy]

I have throated some of the Kahr barrels (Made by Walther) with polygonal rifling, they handle cast just fine as long as you got some freebore in there. Top of the rifling in these barrels is really tight, a good thou or two smaller than conventional rifling. Had to order some smaller pilots before I could throat them.

[onelight]

I am another with HK USPC 45 with no lead problems I have shot an assortment of my cast lubed on a Lyman sizer , and tumbled lubed but most Hi-Tek coated.
My range trips are normally 50 to 100 shots on any one gun and I clean after each session. Cleaning may be a factor on some of the problems we hear about .
I don’t know what gun you are looking at but I have a SA XD-E 45 that is comfortable to cary and shoot it has become my favorite carry.

[3006guns]

The Kahr is actually the gun I'm looking at, so it needs to have the throat lengthened before using cast, correct? I hadn't counted on that and there's no pistolsmith within reasonable distance of my place. I guess I could size the boolits somewhat smaller diameter, or are the grooves standard?

[onelight]

The Kahr is actually the gun I'm looking at, so it needs to have the throat lengthened before using cast, correct? I hadn't counted on that and there's no pistolsmith within reasonable distance of my place. I guess I could size the boolits somewhat smaller diameter, or are the grooves standard?
You can find a bullet with an ogive shape that will work in most guns and or do a plunk test while working up your OAL keeping in mind if you wind up with your bullet deep seated you load must be adjusted to keep pressure safe but I bet you can find a load to work with the stock barrel.

[DougGuy]

The Kahr is actually the gun I'm looking at, so it needs to have the throat lengthened before using cast, correct? I hadn't counted on that and there's no pistolsmith within reasonable distance of my place. I guess I could size the boolits somewhat smaller diameter, or are the grooves standard?

Seating deeper just causes a secondary problem as a poor workaround to the primary problem in most cases. If your boolits won't chamber, just send the barrel and get it throated, it's an affordable one time deal that lets you cycle anything that will cycle through the magazine after that.

Kahr barrels aren't any different than all the other modern manufacturers of 45 ACP pistols, none of them want to put enough freebore in the barrel throat to use cast boolits. They primarily want the gun to be used with factory self defense ammo, and most will run just fine with this store bought ammo. I had a couple of disturbing ftf with Hornady 250gr Critical Defense, I don't think they "plunked" all the way then when the striker struck the primer instead of firing, it just pushed the loaded round a little further into the chamber. Out of 2 25rd boxes of this stuff, I had 3 that didn't fire in the Kahr but eventually were fired in a 1911 without incident. After this I switched to Speer Gold Dot 230gr jhp and it has been flawless since, and yes I did take the throating reamer to the barrel to further insure each round would chamber properly.

I wouldn't let the barrel put you off from buying one, I have carried my CW45 for 5+yrs now and it shoots great, accurate, buttery smooth DA trigger, there is no external safety, the striker does not store energy from racking the slide, there is no preload on the striker unlike a Glock or the XD Springfield or S&W's M&P series pistols. If you plan to carry with one in the chamber, the Kahr is maybe the safest modern autoloader on the market.

[onelight]

Seating deeper just causes a secondary problem as a poor workaround to the primary problem in most cases. If your boolits won't chamber, just send the barrel and get it throated, it's an affordable one time deal that lets you cycle anything that will cycle through the magazine after that.

Kahr barrels aren't any different than all the other modern manufacturers of 45 ACP pistols, none of them want to put enough freebore in the barrel throat to use cast boolits.
Interesting response. I always considered the ability build loads or a specific gun to be one of the advantages of reloading and is what a lot of the discussion on these forums is about.
Also if we cast we can select a mold that suits our needs. Some people may not want to buy a new gun and have it modified in a way that may affect the warranty.
Sometimes there is more than one good way to achieve our objectives. Most choices are a compromise in some fashion.
I think redoing the throat is a good idea but I have seven 45 acp guns they all function and shoot well with the same loads none have been rethroated.

[onelight]

Just wanted to add I mean no disrespect for DougGuy he knows way more about barrels and Kahrs than I ever will and my experience with Kahr is limited to one CW40 that had issues not related to this topic . My knee jerk reaction is a load could be worked out but he has experience with this problem on this model I don’t.

[ioon44]

I have shot many thousand's of Hi-Tek coated 200 gr SWC cast out of my PPQ 45 and never had any problems with leading and accuracy is on par with my 1911's.

[PBlover429]

Put 2000+ rounds of WW cast through a 9mm Glock with no issues. Shot just as well as White box jacketed. Just another "Glock myth".

[FergusonTO35]

The Kahr is actually the gun I'm looking at, so it needs to have the throat lengthened before using cast, correct? I hadn't counted on that and there's no pistolsmith within reasonable distance of my place. I guess I could size the boolits somewhat smaller diameter, or are the grooves standard?

Not all Kahrs have poly rifling. The less expensive CW series have standard rifling. The CW9 I used to have ate boolits no problem, even undersize ones.

[joebaja]

I concur with ioon44. My two most accurate loads for my PPQ45 are a PC'd Lyman 200SWC and the Lee 160 RF HiTek coated. The 160 was a bit tricky to dial in a good OAL for reliable feeding, but it does shoot really well. Better than most plated that I've tried

[Tom W.]

I don't have any more Glocks, but I had a 17, a 19 and a 30, all Gen 4 models, and only three boxes of jacketed bullets were fired from the 17, the rest never saw any factory loads, only cast. I never had a bit of trouble with them as far as function went, no leading, no bulges, no problems....

[onelight]

I think we have two different things in discussion tight throat & poly rifling the Kahr has both I don’t know if the CW45 has a tight throat or not.

[DougGuy]

I think we have two different things in discussion tight throat & poly rifling the Kahr has both I don’t know if the CW45 has a tight throat or not.

There was a bit of thread drift, but OP did mention he wanted to shoot cast so this warrants throat discussion simply because most of us size cast boolits a tad bigger than factory ammo, and in a snug barrel, will often interfere with the throat.

I have done maybe a dozen CW45 barrels with standard rifling and 3-4 other Kahr barrels with polygonal rifling. Yes the Kahr CW45 has a reputation for having a tight barrel.

[onelight]

There was a bit of thread drift, but OP did mention he wanted to shoot cast so this warrants throat discussion simply because most of us size cast boolits a tad bigger than factory ammo, and in a snug barrel, will often interfere with the throat.

I have done maybe a dozen CW45 barrels with standard rifling and 3-4 other Kahr barrels with polygonal rifling. Yes the Kahr CW45 has a reputation for having a tight barrel.
I think it would be hard to not include both in a discussion about auto pistol barrels.

[Good Cheer]

I had one of their .380's a long time ago. It shot great with the SWC #358435. That was before the booger bear stories about polygonal rifling and cast so I was happy to have something new to experiment with.

[Tracy]

I have shot and continue to shoot a limited amount of cast in the factory barrel of my G21. Haven't noticed any problems, but I also have an extended length Lone Wolf barrel for it. I feel better about using the LW barrel.

[tenx]

This isn't about a handgun story but in the early 80's I bought a new Harrington ad Richardson Ultra 300 bolt action rifle in 30-06, this one differed from the usual Mark X mauser action H&R in that it was a SAKO action with a polygon rifled barrel. Not positive if the barrel was made by SAKO or not but it is very accurate. I was a little taken back when I first looked thru the bore when I got it home but I'll take a few more polygon rifled barrels if they shoot as well as this one. Have not shot cast lead thru it yet, I'll get around to it eventually.

[BigAlofPa.]

I have shot many thousand's of Hi-Tek coated 200 gr SWC cast out of my PPQ 45 and never had any problems with leading and accuracy is on par with my 1911's.
I second the Hi-Tek. I run them in my Walthers. No leading expect the problem i had with titegroup powder. But that was across the board.