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40cal.
Apr 9, 2011 18:06:50 GMT -5
Post by Jon on Apr 9, 2011 18:06:50 GMT -5
I have a question for any one that has a 40cal. barrel. What are the land and groove measurements?
Jon
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40cal.
Apr 9, 2011 18:58:44 GMT -5
Post by deadon on Apr 9, 2011 18:58:44 GMT -5
I have a question for any one that has a 40cal. barrel. What are the land and groove measurements? Jon Jon, I do not have a 40 so I cannot help you . I have miced my 45 several times and come up with a different size ea time. Is there an easy way to measure so one knows for sure. Sorry to answer your question with another question, Rusty |
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40cal.
Apr 9, 2011 20:12:01 GMT -5
Post by mountainam on Apr 9, 2011 20:12:01 GMT -5
Jon, Check out Mc Gowen barrels website. They have the specs. I believe they run .400"x.408", but there are about 2or 3 other .40 cal sizes.
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40cal.
Apr 9, 2011 21:06:09 GMT -5
Post by jims on Apr 9, 2011 21:06:09 GMT -5
I tried to find my old notes. Do not take this as gospel but I thought RB said the range was .408-.400 and it was a Cheyene Tactical barrel. I understood it to be a PacNor barrel.
Mine works well with the 200 grain SSTs that are rolled and knurled with a file.
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40cal.
Apr 9, 2011 22:14:54 GMT -5
Post by chuck41 on Apr 9, 2011 22:14:54 GMT -5
Mine is a Pac-Nor. A .400" 200gr XTP bullet in a well cleaned barrel, well lubricated with light oil such as 3n1 or Rem oil will slowly slide down the length of the barrel with only the force of gravity behind it. The dry fit feels snug so I suspect that indicates the lands actually measure about .4005", but I am guessing since I have no way to actually measure it accurately.
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40cal.
Apr 10, 2011 20:18:04 GMT -5
Post by sw on Apr 10, 2011 20:18:04 GMT -5
I have the same barrel as Chuck. It is a 408 Winchester barrel. My 40 cal bullet goes down very easily. When knurled to 0.401", it is lightly snug. I try to knurl to 0.4015" for the resistance I want. Your answer: land to land - 0.401" and groove - 0.408". This goes along with the STD practice of 0.0035" of groove depth. This is my best guess.
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40cal.
Apr 10, 2011 20:34:17 GMT -5
Post by deadon on Apr 10, 2011 20:34:17 GMT -5
I have the same barrel as Chuck. It is a 408 Winchester barrel. My 40 cal bullet goes down very easily. When knurled to 0.401", it is lightly snug. I try to knurl to 0.4015" for the resistance I want. Your answer: land to land - 0.401" and groove - 0.408". This goes along with the STD practice of 0.0035" of groove depth. This is my best guess. Great to see you chime in SW  |
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40cal.
Apr 10, 2011 22:07:07 GMT -5
Post by Jon on Apr 10, 2011 22:07:07 GMT -5
Guys. Thank you for all the input. Very educational. That answers my question completely. Thanks again. In the not so distant future if I'm lucky enough I hope to build a 40 cal. using a full form die for sabotless. And if .357 .40 sabot becomes a reality that would really make my day. Thanks again to all.
Jon
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40cal.
Apr 11, 2011 20:57:30 GMT -5
Post by jims on Apr 11, 2011 20:57:30 GMT -5
Jon: I checked my RB PacNor .40 out tonight. With a .40 SST/SW bullet measuring .400, it slides down the bore dry very easily. No real interference at all. In fact it nearly falls down. But with just knurling it slides easily down the bore but enough obturation must occur to make it shoot accurately. Way less pressure to load than a normal saboted .50 load.
Thus sw must be correct, the lands have to be closer to .401 than .400.
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40cal.
Apr 11, 2011 21:53:17 GMT -5
Post by fishhawk on Apr 11, 2011 21:53:17 GMT -5
Jon, if I was doing a .40 for sabotless with a fullform die, I would go .392/.400. Pacnor and McGowen have this bore. But if we made a sabot for .357/8 most would want it for the .400/.408 bore.
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40cal.
Apr 12, 2011 3:32:36 GMT -5
Post by Jon on Apr 12, 2011 3:32:36 GMT -5
Fishhawk. That is why I'm asked the question. It's a little hard to form a .400 bullet to fit a .400/.408 barrel. If by chance someone comes up with a .357/.400 sabot would I be out of luck with a .392 barrel?
Jon
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40cal.
Apr 12, 2011 5:26:19 GMT -5
Post by moto357 on Apr 12, 2011 5:26:19 GMT -5
dont forget there are plenty of .410 bullets like hornady's xtp 210 or noslers 210 to name a couple. those could easily be used in a full form die to work with the .400/.408 barrel, not to mention those nice hornady 300gr interlocks  |
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40cal.
Apr 12, 2011 7:01:24 GMT -5
Post by mountainam on Apr 12, 2011 7:01:24 GMT -5
Personally I would love to see a .375"x .40 cal sabot. The 220gr .375 Win bullet would probably penetrate better and fly a little flatter than the .40's. Then there are a few 235gr .375" semipoints out there that would handle all the velocity that you could throw at them.
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40cal.
Apr 12, 2011 10:25:54 GMT -5
Post by jims on Apr 12, 2011 10:25:54 GMT -5
Jon: The only thing I have to do with my RB PacNor is roll the SSTs between two files and they work. No die resizing, just knurling. It cannot be much easier than that BUT the factory bullet must be close enough to fit.
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40cal.
Apr 12, 2011 11:39:13 GMT -5
Post by fishhawk on Apr 12, 2011 11:39:13 GMT -5
The reason I mentioned the .392/.400 is if we can get a high BC bullet made in .400 as discussed in a couple other current threads we could shoot it saboted in a .400/.458, sabotless knurled in a .400/.408, and fullformed in the .392/.400. Now then if this happened and I was later making a sabot for .357/8 I might consider doing it for the .392/.400 barrel instead of the .400/.408.
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40cal.
Apr 12, 2011 14:16:20 GMT -5
Post by Jon on Apr 12, 2011 14:16:20 GMT -5
Fishhawk. You have pretty much helped me make my mind up. Especially with people looking into high bc .400 bullets. Now the problem is who makes the best barrel. With so many in progress I'll wait and watch for a while. I'm liking the idea of a cut barrel but have no experience with them and there are a lot of top barrels that are done with a button. I would not make that weigh much in my choice. Again to you and all I appreciate all the help and input.
Jon
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40cal.
Apr 17, 2011 21:46:55 GMT -5
Post by sw on Apr 17, 2011 21:46:55 GMT -5
Both cut and button rifled barrels win 6PPC benchrest matches. There are more cheap button rifled barrel than cheap cut rifled barrels, but this doesn't make quality button rifled barrels bad. Kind of like Kumho tires, a lot of cheaper ones and some excellent ones. Maybe the same could be said for Goodyear tires, but I never had a Goodyear that had a good year. |
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