What should I try in order to make a faster load work in my 30-30?

[Centaur 1]

Well let's see; accuracy started going around 28 gr of 4895 which was probably pushing around 2000 fps+/-. Marlins in 30-30 have 10" twists. Pushing 2000 fps is pushing 144,000 RPM. You have come up against the RPM threshold with that combination of componants. I would suggest working with slower powders that have the loading density to lesson the accelleration. Win 748 and Hodgdon LeveRevolution and H380 come to mind. Another consideration is that that particular bullet is not a good enough design to push above 1950 fps, 140,000 RPM, especially if the barrel of your rifle is a 20" one.

Larry Gibson

BTW; Older Winchester M94s (pre Jap made ones) have 12" twist barrels and can do better, upwards of 22,00+ fps, before coming up to that level of RPM.

My rifle is a Marlin 336SS with a 20" barrel, and 10" twist rifling. I see where a chrony would be a big help. There's not much loading data for the 30-30 with slow powders and cast boolits so I have to assume how fast they're going. If 28 gr of 4895 is giving me 2K, that's faster than I thought. I was going on some quickload data that says 25.9 gr = 1600 fps, and 35.6 gr = 2253 fps. On the other hand Realguns.com data says 22 gr = 1612 fps, so I'm really just guessing at my speed.

leadman, yes I'm using Hornady gas check, I might take you up on your offer after a little more testing. Thanx.

[Centaur 1]

I'm looking some more at jacketed data, I know that it's not the same but I'm assuming that it might be in the ball park. The Hodgdon web site lists 29.8 gr imr4895 at 1938 fps with a 170 gr bullet. My boolits weigh 173gr with lube and check. That's getting right at the 140,000 rpm's that Larry was talking about. 30 grains was as fast as I could go before my group size disappeared, it was 3.3" but by then my barrel was too hot to touch since I didn't have the time needed to let it cool. I'm going to try starting there with a cold barrel and see what happens. I really appreciate the time that y'all are taking to help me with this.

[Larry Gibson]

Centaur 1

I also doubt the 28 gr load was 2000 fps from the 20" barrel. It is close to that from 24" barrels. That's without a dacron filler. With the filler (1/3 gr) the velocities are a bit higher, especially with 26 - 29 gr of 4895. Also the flavor of 4895 can make a bit of a difference.

Larry Gibson

[Jech]

Centaur, I have a Marlin 336SS in 30-30 that had a short throat much like you describe. For plinking rounds, I found that an OAL of 2.432" slightly engraved the bullet but it greatly improved my standard deviations from the 55-65fps range to 25-35fps. RanchDog's plain-base TLC311-165-RF at 2.432" charged with 7.3gr/Unique gives me right around 1200fps and 8.0gr gives 1370fps. My alloy is not optimal yet so beyond that velocity, accuracy takes a nosedive.

Using a gas checked version of the bullet, 30.8gr/W748 lit with a magnum primer again at the 2.432" OAL is pushing 2,000-2,050fps from my barrel. This is my go-to "full power" load as it has shown itself to be very accurate. 1.5-2" groups are the norm with a scope, 3" groups if I'm using my '67 336 Texan which has Williams peep sights.

[Char-Gar]

I have fired thousands of cast bullet loads through various 30-30 rifles. They are a natural combination. I stick with powders that have been around for a long time and which I have worked with for many years. I don't get any surprises this way and consistent good results.

For loads up to 1.7K fps, I use 4227, 4759 or 2400. They all do just fine. When I go higher I uses 3031 a couple of grains down from top end Lyman charges. The velocity of these loads is at or near factory ammo speed. 3031 and 4895 are very close in speed and application and while the charge weights don't interchange, they both give excellent results in the 30-30.

With the right alloy and a gas check cast bullets can be shot at full factory ammo velocities and the same or better accuracy. I use good old Lyman No 2 for these loads. Air cooled WW do just fine for the lower velocity stuff. If you are a hunter a cast bullet from the 30-30 is just as effective at 1.6 - 1.7K fps as higher velocity stuff. Put an ACWW 160-190 bullet of good design, at 1.6K fps into the right place on a deer and you will have a dead deer.

I am certain there are other and more recent powders that do just as well, but I see not reason to change what has worked for me for 50 years. I am a shooter by nature and not a tinkerer or experimenter. I load to shoot and not shoot to load.

[geargnasher]

Gear

Maintain what you will but like so many others Centaur 1 has come up to the RPM threshold of 140,000 RPM and after accuracy went south. Coincidence? But if so there sure is a lot of that "coincidence" isn't there. If you note I gave him some advice on how to proceed beyond the threshold. I have numerous 10" twists that I have pushed the RPM threshold upwards with. Many others have done the same. It is not difficult but it take knowledge and the correct type of bullet and other componants to do it with. The RPM threshold is not a "limit" as you apparently still think it is. It is not as it can be pushed higher as you've done.

However, as BABore also mentions as I did, the design of that bullet may limit it to below the RPM threshold of 140,000 RPM for best accuracy regardless of other measures taken to push it to higher velocity with accuracy. I have pretty much the same bullet only mine is a 150 gr. I have not been successful with maintaining accuracy over 1900 fps in any cartridge with 9.5 to 10" twists regardless of the cartridge or other componants used. In 12" twists I can push it to 2000 fps and maintain accuracy but above that it is not consistent. Next to a long nosed pointy cast bullet that design is the hardest to maintain any accuracy with at higher velocities. Design of the bullet does have a lot to do with it

Larry Gibson

I love jerkin' yer chain, Larry! Don't confuse me with certain other recalcitrant and argumentative personalities you may have encountered in the past, I think your RPM threshold theory is compelling. I know for a fact that I have to do special things to get any gun I have to shoot straight past about 130k rpm with cast.

As has been pointed out, Centaur is dealing with fairly soft boolits with small bearing surface due to the TL grooves, and that is naturally going to have velocity limit relative to lots of things, including your RPM theory. He could go faster with what he has if he used RX7 and some compacting, granular filler, and used .32 Winny brass sized down to .30-30 so he could benefit from a tighter loaded neck diameter, but that's the hard and potentially dangerous way IMO. Water-quenched 50/50 and a boolit with real lube grooves pushed with 35 grains of 748 and Federal Standard Large Rifle primers would probably do much better, maybe even getting to 2.2k fps with some decent accuracy.

Gear

[Larry Gibson]

Not problem Gear, just wanted Centaur to know what he was coming up against. Sometimes not understanding that causes a lot of frustration trying to figure it out. As usual we're on the same page.

Larry Gibson

[Centaur 1]

I'm just glad that I'm not the only one who overthinks every aspect of what I'm doing. Some think it's frustrating, but as long as my findings adhere to the laws of nature and don't give crazy illogical results, I find all of this fun.

Gear, since you have the same design but with standard lube grooves, lets do a little experiment. I measured a RD boolit with a gas check installed. It is sized to .310", and I loaded one long so that I can see where the rifling starts to engrave the nose. Total length is .930". From the tip to where the rifling touches is .265". That meens that .665", or 71.5% of the total length interacts with the bore. I then measure each lube groove, crimp groove, and the gap that's next to the gas check. Total groove width is .186", which gives me .479" of bearing surface, or 51.5% of the total length touches the bore. The only other boolit that I have to compare it with is the Lee 150gr fn, and it's total bearing surface equals only 39.9%. Do me a favor and measure one of yours and see just how much different the amount of bearing surface is.

I can tell already that I'm so anal that I'm going to need a hardness tester before too long. I really don't think that my boolits are that soft. When they are air cooled, I can bend them back and forth with pliers and when it finally breaks the edges look more like they're sheared than broken. After I heat treated them it will bend some then break, the edges are fairly straight and it look grainy and dull. When I water quench this alloy, there's virtually no bending before the boolit breaks with an audible snap. The heat treated boolits will break straight across the crimp groove, but the water quenched ones break differently. One side will have a concave suface and the other is convex. The other test I used was the hammer blow test using a 3lb sledge hammer. The softer air cooled ones can be hammered flat. The heat treated ones, which are the ones I shot, would start to flatten, but they'd mostly go flying out from under the hammer. The water quenched ones would break in half and go flying in two directions at once. Brinnel hardness??? If anyone has a conversion chart let me know. Of course if I had a tester I would have just bored you with numbers instead of my desciption.

I must be pretty close to achieving a good hunting round. The two powders that keep getting brought up, RX7 and 748, one is faster and one is slower than imr4895, and the one constant answer I've gotten was to use a slow powder. I'm thinking about pan lubing some and seeing if I can get them to go a little faster before the groups open up.

[Centaur 1]

Come on Gear, don't let this one die just yet. Measure up one of yours for bearing surface so that I can compare. I think that I'm going to try lubing with lithi-bee, and see how they group.

[geargnasher]

Man, I've been covered up with ASE Recerts, L1A test, and work's been crazy this week. I'll get back to you ...

Gear