38-55 Key Holing.

[ham7777]

My brand new out the box 38-55 sn HW331070  (I have had it about 2 years now )is key holing. I know I read somewhere what to do about this but can not find where that was. So I am asking for help from my Handi buddys.
I was using Meister bullets 245 gr. .380 dia.with SPG lube.with 18.0gr. of 2400 powder.   Thanks for any help  Tom Ham7777

[cwlongshot]

Mornin Tom,
 I would do a chamber cast. Be sure you get some of the barrel in front of the throat. Mike it up and ill bet ypu find your throat is small and bullets your shooting undersized.

Cure will be opening the throat to .400 and firing correctly sized bullets.

CW

[Blackhawker]

I have a Target Classic in 38-55 and I found with certain bullets and 2400 powder that if I really push the load I'll get erratic results, including some key holes.  Part of my problem, however, is that my bullets are only .0005 inches over the groove diameter as opposed to the minimum recommended .001 over groove diameter.  The bullets that have key holed for me were 264gr FPGC's (actual weight 282grains)  The charges of 2400 that I found started the erratic results were roughly 18 or 19 grains.  If you have undersized bullets and push the load, this is the result you'll get. 
Consequently, I've tamed my load down and I get consistent 1.5 to 2.5 inch groups at 100 yards with my Target Classic.

[44 Man]

I'm sure you will find Blackhawker correct.  I would think your bullets are a little undersized.  If they are, you cannot push them fast or they won't bite the rifling.  Also those bullets you are using are very hard, and that doesn't allow them to obdurate and fill the rifling either.  Try a 'softer' lead alloy, but most likely you just need a larger diameter bullet.  44 Man

[quickdtoo]

There are some real good links to the issues mentioned here already in the FAQs, that would be a good place to start.    I've shot 325gr gas checked .380" cast bullets in my HX 38-55 with good accuracy without neck reaming which is also covered in the FAQs. Slug the bore and throat, 4D has several neck reamers to choose from.
 
Tim
 
http://www.gboreloaded.com/forums/index.php/topic,227851.msg1099262629.html#msg1099262629
 
 

[gcrank1]

What other powders do you have to choose from? 2400 is not one of my favorites, especially in a big, roomy rifle cartridge. IMR 4227 at 14-18 gr, (quite a range, that) have all worked well with .379 and .380 bullets of about 250gr., cast of WWt and a dash of tin to Lyman #2 alloy. Currently Im happily using a full case to seated bullet base of Trail Boss.
I have not reamed my rifle's throat yet.
FWIW, the 'convention' of .001 over groove dia bullets vs .0005 is a non-issue, once it gets swaged into the bore either is bore /groove diameter. What is a play is the bullet filling the chamber throat so upon launch and the transition, unsupported, from case mouth to bore, does not result in bullet base band cutting from the propellant gases. A close fit of bullet to throat and/or a softer alloy to 'bump up' helps all this. My .379 bullets fit nicely into a fully expanded (fire-formed) case mouth without re-sizing.

[ham7777]

My day at the range was not all bad I finally got to shoot my 45-70 Classic with a 6X Wm.Malcolm scope by Hi-ux (bought this set up on Gun Broker a while back) It did well 1 1/4 5 shot group using 24.gr. of 2400 and a 300gr.Moyer bullet.
My 44-40(re-chamber from 44mag.) shot a nice 1 group at 50yards with a cowboy action load my brother give me to try. Not sure what the load was will have to find out for sure.
Thanks for all the help with the 38-55 trouble,just order the stuff for casting the chamber have been going to get same for years and never did.
Later Tom

[Blackhawker]

What other powders do you have to choose from? 2400 is not one of my favorites, especially in a big, roomy rifle cartridge. IMR 4227 at 14-18 gr, (quite a range, that) have all worked well with .379 and .380 bullets of about 250gr., cast of WWt and a dash of tin to Lyman #2 alloy. Currently Im happily using a full case to seated bullet base of Trail Boss.
I have not reamed my rifle's throat yet.
FWIW, the 'convention' of .001 over groove dia bullets vs .0005 is a non-issue, once it gets swaged into the bore either is bore /groove diameter. What is a play is the bullet filling the chamber throat so upon launch and the transition, unsupported, from case mouth to bore, does not result in bullet base band cutting from the propellant gases. A close fit of bullet to throat and/or a softer alloy to 'bump up' helps all this. My .379 bullets fit nicely into a fully expanded (fire-formed) case mouth without re-sizing.

gcrank,
I agree that the .0005 over size probably isn't a real problem.  When I slugged my barrel and compared the bore size to the bullets I had purchased, I figured that the bullets would obturate enough to fill the gap.  What I find funny is that it's only the 2400 powder that reacts so erratically as compared to other powders when approaching a hotter load.  When approaching a high limit load (for my particular rifle's accuracy), with the 2400 I get more flyers in my groups and the group drastically moves off target further and more dramatically with a slight increase in load by comparison to other powders.  I can only attibute this to an article I had read by John Linebaugh in which he had stated that 2400 is apt to pressure spikes by comparison to other powders.  (for this case he was comparing to other magnum pistol powders)  Nonetheless, if the powder does often pressure spike, that might explain why I see some flyers now and then when working in the higher end loads.
By the way, my chamber throat is rather tight with these bullets.  I can only go up about .0005" more in bullet size before chambering becomes difficult.
 
Since you offered up some info on powders that you have used in your 38-55, I figure I'll do the same and hope that this might help Tom a bit.
I typically use IMR-3031 under my 264g FPGC's and get very nice and consistent results.  IMR-4198 also works very well.  I had found that roughly 9 or so grains of Unique works very well under these bullets but I am looking for a bit more power than that load can offer.  I believe that load is probalby around 1,200 to 1,300 fps.  Probalby enough to take out just about any deer or even black bear one might run across but I want a bit more velocity for a flatter trajectory.  I've also used IMR-4227.  I don't recall the load off hand but it was rather light as well but gave very nice accuracy.

[crow_feather]

Looking for a 1600 fps, 38-55, sub moa load?  I use WLR primer in a WW case with Beartooth gas checked bullets that weigh 285 grains.  (I believe they sell them as their 265 gr bullets)  24 grains of RE 7 powder moves the bullet at 1600 FPS.  I have shot 4 into 1/2" blowing the group out to .9" with the fifth shot.  I used a 3 x 9 scope on a rifle rest to get the group.  Off hand, it would open to 5".
 
CF

[gcrank1]

Thats quite the little Nitro Express load you've got there!
Dont know if I'd ever need the power of that since I've got the 'big guns', but good to know.

[aromakr]

19 grains of 2400 in that case doesn't even come close to filling it. I will bet the powder when the rifle is in the shooting position can be below the flash hole and your getting pressure spikes because of that. You need something to hold the powder at the base of the case. like Florist foam, a small sliver pressed on to the case mouth then seated on the powder with a pencil should eliminate your problem. This is done all the time with large capacity cases and light loads.
Bob

[gcrank1]

I cant agree with that methodology, though it was commonly recommended in the past. There is way too much evidence now accumulated, and the effect duplicated, that 'wads' such as that, or even Dacron as a wad, pressed down upon the powder can and does cause chamber rings. Usually this effect isnt noticed until cases become hard to extract and a bright expansion ring is noted upon the case neck right where the base of the bullet has been. This is not easily or cheaply fixed and then what good is your marvelously accurate barrel?
I refer you to 'The Modern Schuetzen Rifle' by C.Dell and W. Schwartz; they could duplicate this effect almost at will and with few shots even in modern steel barrels.
What does work is a tuft pulled in to a longish 'fluff' that completely takes up the space as a filler which does not has extra ejecta weight or chance of hardening up like Cream of Wheat or such. That is known to blow bottlenecks off.

[aromakr]

The green florist foam ignites with the powder and will not cause the problems cream of wheat does.
Bob

[rsl]

I had same problem.. Try Lazer cast .380 bullets and Starline brass..

[Blackhawker]

19 grains of 2400 in that case doesn't even come close to filling it. I will bet the powder when the rifle is in the shooting position can be below the flash hole and your getting pressure spikes because of that. You need something to hold the powder at the base of the case. like Florist foam, a small sliver pressed on to the case mouth then seated on the powder with a pencil should eliminate your problem. This is done all the time with large capacity cases and light loads.
Bob

With a straight walled cartridge, one should not consider if the powder fills more or less than half of the empty cartridge's volume if no bullet has been seated.  What matters is if the powder fills more than half the remaining volume AFTER a bullet is seated.  A 264g FPGC, when seated, takes up nearly 1/3 the volume of a 38-55 case.  So, if the empty case is half full with powder, once the bullet is seated, the powder is now taking up MORE than half, in fact, nearly 3/4 of the remaining volume.  Hence, when the case is tipped to the shooting position, the powder is above the flash hole.
There is no need to insert a wad in this load.  I've gone as low as 16.8 grains of 2400 (which by the way is a very good load for my rifle) and have no problems AND the powder is still taking much more than half the remaining case volume AFTER the bullet is seated.
 
I hope I was clear on that and that made sense. 

[Higene]

My Thompson Contender carbine and Big Bore 94 shoot cast lead bullets less accurately than Hornady  200 and 220 JFPs. This was a puzzle to me but the TC was so accurate with 200s that I figured that that was the load the gun liked and I quit trying to impose my will on it. 28-32 gr. Hogden 4198 is what it likes.


  

[gcrank1]

Ham7777, I guess we should starting at the beginning, my apologies.
How does the bore look, good rifling the whole length, etc.?
Have you run a soft slug down a clean and oiled bore to 'feel' it out?, tight or loose spots, etc.
It hasnt come up that the 38-55 is particularly bad in these regards, but one cannot shoot groups with a bad barrel, so lets eliminate that right off.

[ham7777]

Just got out to shoot this rifle again with cast bullets from a Lee mould and it is great I was only able to shoot at 50 yards. But no key holes and it group well under 1"
Also got to try a few shots with my 450 Marlin H&R with factory ammo 350 and 325 it was a hand full off the bench  .It also grouped very well at 50yards. Going to do some hand loading for it.
 
Happy Days are here again.     Tom