TC vs SWC - OAL ? in Target Use with 9mm

[chiltech500]

I don't understand the difference between a truncated cone bullet and semi wad cutter. In pictures they look to be about the same thing. Would someone please explain.

I've purchased 125gr SWC from Mo Bullets and the max OAL I seem to be able to get is 1.130 before having the lube strip peak over the edge of the case. I was using a 1.150 plus with RN. I've read that to have the greatest accuracy it's ideal to have as long a round as possible.

Thoughts, is anyone using the SWC in 9mm and have experiences regarding accuracy?

I need all the help I can get!

 

[sexybeast]

I have found with swc you can't adjust the oal much at all. The shoulder is even with the case, any longer and it won't chamber. Round nose gives you the most oal variance. Truncated gives you less where if its too long the bullet will impact the rifeling on chambering and it won't go into batery.
Do the "plunk" test with all of your loads. If it won't go into battery because its too long its best to find out before going to the range.
Do a search on "plunk" and you will get more info on this. OAL is just a starting point, as you are finding out not all bullets are the same as what they use in loading manuels.

 

[chiltech500]

Done the plunk test and the 1.150 RN fits fine, the LSWC fits fine at 1.130

Titegroup data for the 125gr shows 1.125 so I am close. I have also loaded some 1.110 LSWC which plunk fine but I thought I would try the longer 1.130 to see if it was any more accurate.

I still don't understand the difference between the TC shape and SWC and how it affects feeding, target imprint, etc.

 

[deadeye dick]

Done the plunk test and the 1.150 RN fits fine, the LSWC fits fine at 1.130

Titegroup data for the 125gr shows 1.125 so I am close. I have also loaded some 1.110 LSWC which plunk fine but I thought I would try the longer 1.130 to see if it was any more accurate.

I still don't understand the difference between the TC shape and SWC and how it affects feeding, target imprint, etc.

Me neither ,please explain.

 

[GJSchulze]

A SWC has the shape of a new Crayon. A TC has the shape of a sharpened pencil that's cut off at the point so that it has a flat top. IOW the SWC has a ledge around it. I believe it's the ledge that catches when there's a FTF.

 

[rsrocket1]

The SWC is a compromise between the wadcutter (essentially a cylinder) and a pointed or round nose bullet. Wadcutters punch nice crisp holes in paper targets. Obviously you can't feed a wadcutter in a autoloader so a SWC is used if it can feed properly. It also has a slightly higher BC for better ballistics.

TC's if designed right, have no shoulder and provide better feeding. Some TC's like the Lee tumble lube designs have a slight shoulder which could either catch a rearward moving empty case or cause a feed jam. TC's are better than "completely pointy" bullets in autoloading handguns and are more forgiving in chambering throughout different types of pistols than roundnose bullets.

Hope that helps.

 

[dickttx]

Go to this website and look at the 9 Cone and the 9 SWC. You can click on the image and get a larger picture.

http://www.missouribullet.com/results.php?category=5&secondary=8

 

[chiltech500]

Excellent information thanks.

Is it the shoulder on the SWC that creates the nice paper hole, not the flattened nose?

Interesting that the TC should feed more reliably than RN because it doesn't seem like they are that popular.

 

[rsrocket1]

Is it the shoulder on the SWC that creates the nice paper hole, not the flattened nose?

Yes, it is the abrupt shoulder that punches the nice hole. A gradual expansion of the hole tends to rip the paper. I use the Lee 358-158-RF which is a "round nose flat point" bullet which is almost as flat as a wadcutter, but it feeds a little better into the cylinder of a revolver than a pure wadcutter. The big metplat does punch a cleaner hole than a RN or TC bullet, but still not quite as good as a WC or SWC.

Here's what the Lee cast 9mm TC looks like. The cartridge on the right is the Lee RF bullet for 38/357:


Here's a sample of what the 9mm TC looks like when it punches paper. Good for general target practice, but a SWC punches a cleaner hole which is easier to score when in competition shooting:



Here's the Lee 9mm Tumble lube round nose bullet. Notice the shoulder. Even though it looks like it could cause a problem, I got 100 from a fellow caster and tried them out. They worked perfectly with no hangups.


Here's the 9mm TC, note the lack of shoulder.

 

[GJSchulze]

Here's a sample of what the 9mm TC looks like when it punches paper

I've noticed that my 9mm TC cuts a cleaner hole than does any round nose. The edges on the round nose really look like you could put them back together to hide the hole. You can not do that with the hole a TC makes.

 

[chiltech500]

Thanks so much rsrocket, you put your time and effort into that post and I really appreciate it.

I seek budget but don't really want to get into casting because I'm mildly handicapped and would have to cast in a detached garage and too much back and forthing while carrying things.

I was seeking a budget SWC for 9mm for targets just to save a few dollars but Mo Bullets does have 125gr SWC. Now I know the TC is a cleaner hole than the RN but a SWC is still best for competition.

I plan on shooting NRA Bullseye when I get a bit better but I'm clearly better off with my 45 and its' much bigger hole