.38 Super - Success, and failure

[Grandpas50AE]

In another thread I detailed my difficulty with some custom sized Penn 147 gr. TC BB boolits. I had leading with them as delivered, so I melted the lube out of 50 of them and re-lubed with Javelina 50/50 lube. They were custom sized at .3565". After the lube change, there was no more leading. These were loaded with SR4756 (6.3 gr.) giving 1150 fps. While contempalting all that, I ordered a mold from Accurate Molds, number 35-140S, casting out at 142 gr. I loaded several loadings from 5.5 to 6.5 gr. SR4756, and these were cast of pure WW, air cooled and aged for 1 week. These were sized at .3568" and lubed with Javelina. I managed to get to the range with these yesterday, and got some fair amount of leading. It may be the 5.5 gr. loads (shot 10 at 5.5, 10 at 5.8, 10 at 6.1, and 10 at 6.5) that did most of the leading, but it may be the 6.5 gr. loads. Judging by the success of the Penn with the same lube, I suspect the lower loads gave most of the leading, but not sure.

So tonight I took the advice of others in the other thread, and tapped one of my 35-140S (SWC) out to .3665" and slugged the bore, it came out at .3562". Now that I finally have some tin, I plan on adjusting my alloy by adding 2% tin to the melt and casting again, same sizing. The Javelina lube ran out, and has been back-filled in the sizer with BAC from While Label. I plan on using the 6.5 gr. load to stay close to the success I had with eliminating leading on the 147 gr. Penns loaded with 6.3 gr. SR4657.

Thoughts, observations, suggestions?

[WineMan]

Fatter (I go 0.358" and 158 grains) and if you have an original Colt headspace on the semi-rim barrel, have the nose of the bullet into the lands. This gives a nice firm headspace and shrank my groups at 25 yards by several inches. A newer Bar-Sto barrel will headspace on the case mouth so just go with a fatter bullet. I like mine a bunch but at the range chasing the brass is a real pain with all the 9 mm laying about. I broke down and got a 9 mm barrel to use when at a public range.

Wineman

[Grandpas50AE]

My apology, I meant to say it was in a relatively new Kimber, so it headspaces on the case mouth. As far as accuracy, the 7 yards I shot at was not a good measure, but most were going through a ragged 1 1/4" hole. POI was POA, but again, at 7 yds. it isn't a good guage of accuracy potential.

[BossHoss]

My apology, I meant to say it was in a relatively new Kimber, so it headspaces on the case mouth. As far as accuracy, the 7 yards I shot at was not a good measure, but most were going through a ragged 1 1/4" hole. POI was POA, but again, at 7 yds. it isn't a good guage of accuracy potential.


Got a picture of the the boolit?

I found a TC 155 for 38 super from a local caster in Northern Il, it has been my favorite for more than 20 years.

I will get a pic of it, don;t know the name of the mold manufacturer.

[Grandpas50AE]

I'm not able to take pictures and post them, my old cell phone doesn't take close pictures worth a hoot. You can see a drawing of it on Accurate Molds website, it is the 35-140S in the catalog. I have a TC that is now performing well, but I am wanting to work with a SWC style boolit in the 140 gr. weight. The 125 and 130 gr. J bullets don't shoot well at any loading, probably due to both size (9mm) and twist rate. The only jacketed or plated I've seen in the diameter .356 for 38 Super are RN 130 gr. which don't shoot well either, and that isn't much to choose from. I have been looking for the old Speer .357 boolits that were 3/4 jacket SWC in 140 gr., but haven't been able to find anyone that can even find them to order any more, so I decided to cast my own. The leading I'm getting is in the last 2/3 of the barrel (none in the first inch or so), and at some point I'll probably get another mold or two in the same weight with different nose designs.

[Bwana]

I looked at that picture and the only thing that I noticed is it seems to have a lot of boolit seated in the case which could result in increased pressure and possibly a reduction of the boolit base diameter allowing blowby which can cause leading.

[bobthenailer]

I have 2- 1911s in 38 super , one has a Nowlin barrel the other is a Kart barrel, both shoot bullets sized to .357 better than those sized @.356 dia

[MtGun44]

Likely too small. You'll want .357 at minimum, and I'd try .358 to start. I've shot about
70,000 rounds of .38 Super with boolits, all .358 diam 147 to 158 gr. Not much leading
even with the stupid crayola commercial lube if they are big enough. I tried .356 one time,
half hit sideways.

Bill

[Grandpas50AE]

Well, after several observations by the knowledgable folks here, I decided to dig a little deeper into the problem with the .38Super. I have seen several mentions of seating a boolit and using a bullet puller to remove it and then measure it. It was an eye-opener for sure. Before seating, my sized and lubed boolits were showing .3572 to .3577 on the micrometer, but after seating and pulling, they mic'ed at .3556" - definitaley swaged down by the casing. I had begun thinking about the expander plug after reading another thread here where GearGnasher had suggested this to someone, and after considering that this was a set of dies for "9mm / .38 Super, I became suspicious that the expander plug was dimensioned for 9mm. Upon examination with the micrometer, sure enough the expander plug was only .3553" to allow for tension on a 9mm boolit. This is well undersized for my barrel that slugged at .3562". This is why I'm having leading problems. I also noted that the expander plug is only .280" long, and needs to be .345" long to accomodate the longer boolits running 140 gr. +.

Since this is a Dillon RL550B using the Redding dies, I will call Dillon tomorrow to see if perhaps a slightly modified .357 expander plug might do the job a bit better. I'm thinking that the .357 expander (powder through die) might have to be shortened slightly, but is likely to be the right diameter. Those of you shooting .38 Super, is this something you ended up having to do?

[Buckshot]

..............Yup. I made a new one for my Dillon 450, and just use a Lyman "M" type casemouth expander intended for the 38 Special when loading 10 round test loads singly. My Witness in 38 Super slugs .357". Have to watch what brass you use if you have a 'snuggish' chamber.

................Buckshot

[Grandpas50AE]

Thanks Buckshot, got the replacement coming from Dillon.

[Grandpas50AE]

After receiving the expander plug from Dillon for the .357, I seated a sized boolit in a case that had been through the sizer then expander. No more swage-down of the boolit, after pulling the boolit it remained at .3572". Thia is exactly .001 larger than the groove diameter of the barrel. I loaded the remaining 70 boolits with my SR4756 load a few weeks ago, and finally made it to the range to test yesterday. Noticably less leading, but still some there, and accuracy through the 70 reounds I shot did not appear to suffer. Still, too much there for my tastes since it took about 3 scrubbings to get it all removed (brush only, didn't need copper Chore Boy this time). All leading occurred 1 1/2 inches beyond the chamber area to the muzzle. There are machining chatter marks in the middle portion of the barrel, and although they are not terribly rough, I belive they are responsible for gas leak and cutting that produces the leading down the remainder of the barrel.

So, here is where I will ask for opinions and advice again. The chatter marks from cutting the rifling in the barrel can be removed by fire-lapping or by hand-lapping. 1) I have hand-lapping compound (Corbins CBL-4) that I can use, which will take a while to lap enough to remove the machining marks. 2) I can buy some boolits that are pre-made for fire-lapping and load them to fire-lap the barrel. 3) I live close to Schillen and can take the barrel to him to have it professionally lapped.

Which would you do, and why? If I choose #1, it will be my first experience with removing enough barrel material to eliminate machining chatter marks and I would want to be sure I keep the dimensions equal through the entire length of the barrel. If I choose #2, which I have also never done before, I would need to know where I can obtain the pre-made lapping compound boolits of the correct size to load and shoot to fire-lap. If I choose #3, obviously it takes my inexperience with lapping out of the equation.

[bobthenailer]

Ive used both methods of lapping ! being that the barrel can be removed and mounted in a vice i would try the hand lapping first as this is the easyest method, just use a bore centering cone that the cleaning rod can slide through when lapping . the fire lapping requires more work on your part but may be the best method of the 2 and definatly the only method i would use on a revolver.

[geargnasher]

Before I did anything to the barrel I'd be on the "horn" with Kimber and see what they'll do about it first. Don't mention "reloads" or "cast bullets", mention it snags a cleaning patch or something. The customer is always right, right?

Gear