30 Carbine OAL question

[Hoss Smith]

I use an RCBS press and dies from the sixties the press resembles todays rock chunker. The issue I am having is inconsistency with the OAL. I have the die screwed down tighter than Dick's hatband and I take the ram to the top on each stroke but I get varying over all lengths. I quit adjusting the bullet seater when I realized that it had to stay put if everything was tight and I will get a number of fairly consistent rounds but they are not all the same. I have measured the bullets (ancient Speer 100 grain SP) and they are a very consistent length some of my cases vary in length but I am not thinking that would affect the OAL of a loaded round account the length from the case seat to the bullet seat ought not to vary. I have a round here in front of me that measures out at 1.691" when I am attempting to achieve a consistent 1.680". I showed it to one of my carbines and it refused to swallow it.

I need some advice from y'all that will get me going. Please use short words and don't assume I know much account I may miss your point.:banghead:

 

[velocette]

Hoss;
The important thing to remember is that the .30 carbine headspaces on the case mouth. This means that the case length is important. If it is too long, the bolt may not close fully with disastrous effects. If it is too short, you may get light primer hits. The maximum case length is 1.290", do not exceed it.
I trim to 1.280 and check every case after re-sizing as they do stretch a lot.
Cartridge overall length on a.30 carbine is really not critical. The variations you are seeing are probably due to slight variations in the shape of the bullets nose. Your seating die contacts the sides of the bullets nose to center it in the die, variations in the shape of the nose will cause variations in OAL.
As long as the ammo will feed properly and fit in the magazine and is not shorter than published minimums you are GTG.

 

[gatorwade]

Subtle shape variations of the SP bullet nose, as Velocette points out, seem the likely culprit. See if OAL variations are reduced with jacketed bullets. I am new to 30 Carbine loading, and haven't found any SP bullets, so don't know for sure. But I do know that SP 110's from factory Winchester and Magtech provide excellent accuracy through my Underwood with no feed problems. When I started loading 6.8SPC I tried ProHunter SP's and found the same inconsistency in OAL. I loaded the 6.8's on a Dillon 550, but am now using a Rock Chucker, trying to find the best load for the Underwood. Extreme and Sierra 110 gr. copper plated bullets, though different diameters, both load very consistent OAL's in the Rock Chucker for me anyway. But full disclosure, I am new to this reloading adventure, so my comments aren't based on the extensive experience of others on this forum.

 

[Sunray]

Only ever used Speer 110 FMJ's or HP's on a single stage, 70's vintage press myself. You using a taper crimp die? Mind you, it's more likely to be a loose seater plug. RCBS will replace it for free(life of the kit, not the owner warrantee. Ditto for your Rock Chucker.), but giving 'em a call might be an idea anyway.
The press give you any grief with other cartridges?

 

[HOWARD J]

Are you using Speer Plinker bullets--the ones with the large lead nose?--if so you will have a small different depth with each cartridge
Does your RCBS seater die come with more than one seater plug--if so try a different one---it may work better.
when trimming your brass stay close to 1.280" don't go below & do not allow any brass to be reloaded that exceeds 1.290" ( this is a warning)
ENJOY

 

[Rule3]

I use an RCBS press and dies from the sixties the press resembles todays rock chunker. The issue I am having is inconsistency with the OAL. I have the die screwed down tighter than Dick's hatband and I take the ram to the top on each stroke but I get varying over all lengths. I quit adjusting the bullet seater when I realized that it had to stay put if everything was tight and I will get a number of fairly consistent rounds but they are not all the same. I have measured the bullets (ancient Speer 100 grain SP) and they are a very consistent length some of my cases vary in length but I am not thinking that would affect the OAL of a loaded round account the length from the case seat to the bullet seat ought not to vary. I have a round here in front of me that measures out at 1.691" when I am attempting to achieve a consistent 1.680". I showed it to one of my carbines and it refused to swallow it.

I need some advice from y'all that will get me going. Please use short words and don't assume I know much account I may miss your point.:banghead:

No a 1.691 COL will not fit when the max is 1.680

Correct, that the case length will not effect your COL but if you brass is to long as it spaces on the mouth that will cause you problems.

Size your brass and measure it to see if it needs a trim. If it doesn't then measure your bullets. I suspect as others the lead nose variance.

I had a problem with some 110 blems that were supposed to be fine other than discolored but found they had different lengths. I Measured them all and separated into 3 distinct piles. and set my seating die for each batch.

 

[345 DeSoto]

If you don't trim the cases all to the same length, on a cartridge which uses the case mouth to headspace, then the Cartridge Overall Lengths will all be different. It's that simple...

 

[Rule3]

If you don't trim the cases all to the same length, on a cartridge which uses the case mouth to headspace, then the Cartridge Overall Lengths will all be different. It's that simple...

No I do not agree with that. Your COL is just that a COL before cambering it's not headspacing.

If you try to seat a bullet with a cannelure and want them all to line up the same then the cases need to be trimmed the same.

Minor different length brass does not change the COL when seating a bullet, that is set my the die.

 

[forestswin]

Hoss

I noticed the same COL differences when I started reloading 30 carbine last week. Mine were 1.680" and shorter - none any longer than the 1.680 maximum.

I made some measurements and found there were differences in the bullet nose.
(I removed my seating plug and used it with the bullets as a comparator - sort-of) all of those measurements were a constant - so that says the differences are in the bullet nose.


I'm going to try what Rule 3 suggested and measure and sort through the bullets lengths and see if that will give me a relatively constant COL.

Or

I may try a flat seating plug on a few dummies and see if there are any issues seating them straight.

 

[tightgroup tiger]

check the seating stem in the seating die to see if the profile of your seating stem matches the profile of the seating die.

You could be squashing the soft points of the bullets a little with the wrong stem in the seating die.

I ran into this once and it drove me nuts until I discovered the tighter neck tension of some of my cases was enough to distort some of the bullets because they really didn't fit my seating stem very well.

It's a long shot but worth checking.

 

[forestswin]

345 DeSoto

I had to sketch this up awhile back to "figure things out"
I hope it helps.

Rule 3 is correct, variations in case length won't change the COL, but if you want to hit a cannelure or a crimping groove all in the same space - you have to trim the case to the same length.

 

[gamestalker]

OAL variations are generally the result of variations in olgive location on the projectile. Remember, bullets seat off the olgive, the seating stem contacts the olgive during seating, therefore if that bullet has inconsistencies in olgive location, which all do, even match grade bullets, they will seat to varying oal's.

GS

 

[Hoss Smith]

Reply

Whew, ask a simple little question and get more education than the law allows - for free. Wow! I am more than thankful for all ya'lls reply. I expect the main problem now is from how the bullet seated account of it's shape. The rounds I seated before and after it all were within limits and were approved by the same carbine that refused this round so this over length must be due to the bullet shape. The case measures out at 1.281 as best as my digital dial caliper will measure it with the bullet still in place so the case length is acceptable but the OAL or COL (according to your preferred abbreviation) is still 1.691 which is just too long for the chamber.

I also had inconsistencies with my old original Forster case trimmer no doubt caused by the operator. I bought a Forster case holder for my drill press and after some considerable fiddling with it produced quite consistent case lengths. Admittedly I sized them to the 1.285" length account I didn't know if I could go shorter. I enjoyed the fiddling part about as much as making holes in paper so I am going to reset my press so that I can resize to 1.280" now that I know that is a good safe length. I have a few thousand cases so messing up a few to get a good set up is not a concern to me.

Those cases that are a bit short of the .280 mark need to be discarded? How short is too short to be safely used and what could happen if I do load some shorter cases?

Thanx again for the education. I expect I will be back for more before I age out.

 

[Rule3]

The case trim to length for the 30 Carbine is 1.280 (Hornady)or 1285 depending on what data you look at

The Max case length is 1.290

Usually done with a sized case. So anything in that range is fine.

Simply seat your bullet deeper for a COL of 1.680

If you bullets are all the same exact length then it sounds like a die set up problem.

 

[HOWARD J]

I don't know how far below 1.280 before your firing pin may not set off the cartridge--nothing will happen except you may have ruined a good piece of brass.
are you loading Speer plinker bullets?
Does your RCBS die have more than one seater plug?

 

[Hoss Smith]

HOWARD J reply

Yes these are Speer Plinkers made back in the 60's. I have another seater plug in the .38 die set. I now have some brass to recycle account of being shorter than 1.280. Me and my old Original Forster just didn't hit it off very well this time but the drill press will hold within .002 which I can just tolerate although that is plenty close enough for the cartridge. I have some Sierra 110 gr. HP's ordered and I am hoping they will be more consistent in COL.

 

[Hoss Smith]

Rule3 reply

As soon as I have time I will get my thinking cap rounded up and make another study of my die and the way it is set up. But in my vacuous mind it seems like if nothing is loose or moving then the results should be the same pretty often as long as the bullets are the same account COL is not related to the brass length. Perhaps I am suffering from more operator error (most likely).

 

[Captaingyro]

But in my vacuous mind it seems like if nothing is loose or moving then the results should be the same pretty often...

Velocette actually gave you the info you need to wrap your mind around this, but it was kind of hidden in the rest of his answer. Don't feel bad, it took a while for this lightbulb to turn on for me, too. Here's the skinny:

Like you say, it seems to make sense that, since nothing is moving, every cartridge ought to come out of the press the same length. We tend to think of the press as a vice...you squeeze from both ends, and stop at the same place every time, so the cartridges ought to all be identical. The problem is, the press isn't pushing against the tip of the bullet. That's how a vice would do it, but the seating stem actually contacts the bullet down lower, somewhere on the sides of the ogive. Have you ever seen a faint ring around the nose of your bullets after seating? That's where the mouth of the seating plug is making contact. Nothing is pressing against the actual tip of the bullet.

So, unless every bullet is identical, that contact point will vary from bullet to bullet, thus giving you a variation in COL. On some bullets the contact point will be higher and the bullet will get pushed deeper, resulting in a shorter OAL. With other bullets you'll get the opposite effect. When you use your calipers you measure from the bullet tip, but that's not where the seater was pushing.

If you want to get an accurate idea of COL using the same point of contact on the bullet as the seater, get a set of these:

http://www.midwayusa.com/product/231904/hornady-lock-n-load-bullet-comparator-basic-set-with-6-inserts

 

[mdm]

Are you crimping? If so, how? I've found with the .30 carbine that if I crimped with the seating die the OAL would vary. Adjust the seating die so it only seats the bullet and do what crimping you need with a separate die.

 

[Hoss Smith]

mdm, Captaingyro

mdm, I am not trying to crimp I don't think. I think I am just seating the bullets. I have the die set like RCBS says, that is I screwed the die into contact and the raise it one round and locked it down. I am getting no case bulges and the bullets seem to be tight in the cases.

Captaingyro, thanx for the explanation. Yes I have seen the rings in the lead and they are not all in the same place by any means. I now understand that measuring the length end to end won't work account the seater does work on the end. The rings are light on most of the bullets but some really show a heavy mark making me wonder just what that does to the aerodynamics of the bullet. Of course I doubt that my ability to hold the shooter still could have anything to do with the point of contact on the target.

 

[gamestalker]

If you want to know for certain that your die is not crimping, put a resized empty piece of brass in the sell holder, run the ram to full extension, then thread the seating die is all the way. If it contacts the case mouth before the lock ring bottom out on the press, you are crimping, how much depends on how much further the seating die will thread down. This is also how you can adjust the crimp on the seating die.

GS

 

[Hoss Smith]

Reply gamestalker

Thanx, I checked and I am not crimping.

 

[sigman2]

As mentioned earlier the differences in the bullet's ogive can cause different overall lengths. However, the differences you're claiming seem excessive. As suggested, check the seating plug fit. Also, check the seating plug itself that it's screwed in tightly on the stem (if applicable). Another thing to check is for debris in the seating plug cup. I've seen bullet lube and other dirt just about fill the cup. If it were me, I strip my die set completely down and start with a thorough cleaning then take it from there.

Also, as mentioned earlier, the case length has no bearing on the finished OAL of the cartridge. The distance from the bottom of the shell holder to the bottom of the seating plug's cup doesn't change unless the die, plug or stem is loose or re-adjusted by the operator.

I have a set of Lyman .30 Carbine carbide dies that I had to put Loctite on the expander plug threads because it kept loosening and changing my flare depth.

Another thing I've changed in my reloading methods is elimination of the flare on straight or tapered cases like the .30 Carbine. If I'm using jacketed bullets I set my expander die to give a full expansion but stop just shy of the flare. That way there's no need to do a "touch crimp" to remove the flare. If loading cast bullets a slight flare is necessary. Think about it, you don't flare a bottle necked case unless you're loading cast bullets.

Good luck

 

[Hoss Smith]

sigman2 reply

Good idea. I will dismantle it for a lookysee. Thanx all for your advice!

 

[CoalTrain49]

Are you crimping? If so, how? I've found with the .30 carbine that if I crimped with the seating die the OAL would vary. Adjust the seating die so it only seats the bullet and do what crimping you need with a separate die.

This will solve the problem. I hate those seating/crimping dies. Biggest PIA ever invented.