Lube Recommendations for High Velocity Rifle Loads?

[nicholst55]

I want to develop some rather high velocity cast boolit loads for some of my .30 rifles - around 2500 fps is the goal. I realize that I'm going to need a hard alloy like linotype, bit I'm unsure about lubes suitable for this velocity range.

Any recommendations? I'm using FWFL for pistol boolits - would that be suitable?

Another idea that I'm looking to try is paper patching. It may actually be easier to achieve my velocity goal that way.

[felix]

Yes, but paper patching will allow even faster speeds, until about 3000 fps is reached. Then, a good lube would be about the equal to patching because the boolit dwell time in the barrel is too short for any significant lead/lube accumulation. Other factors will determine accuracy potential over 2400 fps, no matter the jacket material: lube, paper, metal. ... felix

[Larry Gibson]

Agree, PPing is probably the best way to meet your goal. High velocity of 2500 fps is easy to obtain with regular cast bullets in any .30 cal cartridge normally capable of that belocity. The trick/problem is doing it with accuracy and what your definition of accuracy is. If your rifles have 10 or 12" twists then it becomes problematic regardless of your definition of accuracy. With a 14" twist barrel 10 shot 2 moa groups can be had with consistency at 2400-2500 fps but it still takes some knowledge, the right bullet and componants and the correct technique to put it together.

I have thoruoghly tested the following lubes out of 5 different .30 cal rifles (three .308Ws and two 30-06s) up through 2600+ fps; Javelina, Xlox 2500+, Carnauba Red 2700+, LBT Blue and LBT Blue Soft. All of them work well at 2400-2500+ fps. I did not find any one that gave a definate accuracy edge. The statistacal difference between averages remained too small to call. The order of precedence changed with each test. I still have some of all of them and am currently working with Xlox 2500+ in the 24-2500 fps range and it is working fine. I will finish using them all a tube at a time and will perhaps have a better idea in the long run of which one perhaps works best.

Larry Gibson

[nicholst55]

Larry, what kind of accuracy can I reasonably hope for with a 10 or 12" twist rifle at the velocity I hope to achieve?

[Pat I.]

LBT Blue and good luck.

[runfiverun]

stay away from bore riders and the blue has a rep for the h/v
good luck.... i've hit 2300 with good accuracy [1"+ range] for 10 shots.
the slower twist bbl will be your friend here.
and i am surprised larry didn't mention that a 14 twist would be close to what you want, the rest is in the testing/trying.
go with a soft long burn launch.

[JeffinNZ]

I am inclined to believe there is often too much emphasis put on lube. If you get the BHN right and the bullet fit correct you are a long way there. I use exclusively a lube formulated for BPCR but it allows velocity up to 2700fps (that I have tested) without a problem providing I have got the other factors in check.

[Larry Gibson]

nicholst55

LBT Blue and LBT Blues soft are both good lubes at 2500+ fps but so are numerous others. JeffinNZ is correct; "there is often too much emphasis put on lube". It is the other factors such as BHN, burning rate of powder, etc that will have a much greater effect.

Your question of "what kind of accuracy can I reasonably hope for with a 10 or 12" twist rifle at the velocity I hope to achieve?" is a good one and often asked. However first you must define what "accuracy" is composed of for you. Is it 2-3 shots taken during the course of a day? Is it "sufficient for deer" accuracy? Is it sufficient accuracy for 22 shot strings for High Power competition? There are many individual requirements as to "accuracy" depending on a shooter's wants, needs and desires.

What ever the standard you set for for yourself for "accuracy" of a given cast bullet load in a given rifle/handgun there are several ways to measure it. One method is to zero the rifle/handgun at a given range and then shoot one shot at the same target on different days from various positions. That is a good measure of the combination of accuracy between the ammo, the rifle/handgun and the shooter under varied conditions. It perhaps is the best way to measure "practical accuracy". However I believe you are more interested in the intrinsic accuracy of a rifle with a cast bullet load. There are several accepted ways to measure this and I’ll just mention a couple here as I’m sure many others have their own variations. Nothing wrong with the variations as long as there is a useful number of shots fired under controlled conditions (using a solid benchrest being the most important one) to get a valid statistical comparison.

So let us discuss a couple of accepted methods of measuring “accuracy” of a rifle load. The solid bench rest is a good place to start as is the testing under “good” conditions. The attached photo shows my set up at my local range. You can see I’ve quite a large “bursting radius” when testing. Conducting the tests at a minimum of 100 yards is also necessary. Groups should be measured CTC to at least the first decimal with further decimals not really being that meaningful. It is the measurement of those groups that give us “accuracy”. If at all possible use a chronograph. The chronograph measures the consistency of each string of shots. Pay attention to both the SD and the ES. Many pay too much homage to the SD alone. Just remember the SD/ES are only measurements of consistency, not accuracy. It is the groups that give us the measure of accuracy. However a mutual combination of accuracy and consistency in the loads is desired for a cast bullet load that will be accurate over a span of different ranges and shooting conditions.

Many will shoot a series of groups (3 or 5 shots) of various powder chargers when working up a load. They then proclaim the smallest group as the most “accurate” load and go with that. I have been guilty of this in the past as that used to be the accepted method. The problem was when that same ½” cloverleaf "wallet” group load was shot the next day/week it shot 2”! The problem was that we did not fire a large enough sample of that load to statistically validate it’s accuracy in our test of just one 3 or 5 shot group. There is what is called “random dispersion” and it is real. Within any 10 or 20 shot group of even mediocre accuracy, say 3 -4 moa, we can always pick 3-5 shots out of that group that are going to be sub moa. Now if instead of firing 20 shot group we had just fired 5 shots and those 5 shots just happened to be (that’s the “random” part) those that would have shot that sub moa group. We could brag all we wanted to but to replicate that group the next day would be difficult because the actual accuracy potential of that load was 3-4 moa and it is entirely probable that subsequent groups fired with that same load would have demonstrated that. Thus we see that one 3 shot or even one 5 shot group is not a reliable indicator of accuracy. So what is?

It is my experience that one 10 shot group or three 5 shot groups are the minimum that is required to reliably demonstrate the accuracy potential of any load and provide ta statistically valid sampling. I like to initially test with 10 shot groups and then validate the load with three 10 shot groups because it fits my style of shooting better. Others like to shoot five 5 shot groups and then average the size of the groups for a measurement of accuracy. That is okay too except that they need to remember that the “average” group size is not the accuracy potential of that load. The largest group fired is. However, as long as the number of shots gives us a statistically valid sample and the measuring is consistent the “accuracy” potential can be accurately measured.

Let me mention (since runfiverun mentioned it) that the use of a 14” twist barrel, or a even a slower twist, give you a running head start on obtaining accuracy with a cast bullet in a rifle. In .30 caliber rifles this means a “Palma” barrel or a custom barrel. Also the use of 24” or longer barrels is also best as it affords the attainment of high velocity with less time/pressure curve (acceleration) applied to the cast bullet as with a shorter barrel to achieve the same velocity. However since most common .30 caliber rifles come with 10 or 12” twist barrels with 10” twist being the most common we shall specifically address those here to answer your question. The exception to the 10/12” twists is the very few “Palma” style rifles (like Savage’s) with 13 or 14” twist barrels. Controlling the rate of RPM through the twist of the barrel is the easiest way to accuracy with cast bullets at high velocity.

The last very important item I want to mention here regarding cast bullets in .30 cals at high velocity (2500+ fps) is the design of the cast bullet itself. To achieve such high velocity is easy with any cast bullet of a weight that is appropriate for bullets in that cartridge. However to do so with any accuracy requires a certain design of cast bullet. The cast bullet should have a bearing length of such that the base of the GC is at the base of the cartridge neck and the front driving band/shoulder is just slightly being engraved by the leade in the throat. The sized diameter of the cast bullet should be exactly the diameter of the ball seat/freebore of the throat if there is one. If there is not a ball seat/freebore then the sized diameter of the cast bullet should not exceed .002” over the groove depth of the rifle barrel. There should be a very short nose with minimal ogive. There should be no bore riding part to the nose. The nose ogive should begin right at the front edge of the front driving band or at the shoulder. The lube groves should be shallow and not over .299” deep in diameter. There should be sufficient lube grooves to hold enough lube. The two best bullets that generally meet this criteria for most .30 cal cartridges are the LBT bullet and Lyman’s Lovern style 311466.

So now with all the above in mind let us answer your question of; “what kind of accuracy can I reasonably hope for with a 10 or 12" twist rifle at the velocity I hope to achieve (2500 fps)? Given an accurate rifle capable of consistent 5 shot moa with jacketed bullets with a barrel of 24”+ you can expect the following.

Using either of the above bullets with a 10” twist at 2500 fps using one 10 shot group or three five shot groups as the accuracy measurement; 6-8 moa if you use the right other components and if not you’ll be lucky to “hold paper”.

Using either of the above bullets with a 12” twist at 2500 fps using one 10 shot group or three five shot groups as the accuracy measurement; 4-6 moa if you use the right other components. If you tone it down to 2400 fps then 2-3 moa is very achievable. Just the other day (when the photo below was taken) I shot a 15 shot group into 2.85 moa at 2408 fps out of my 12” twist M70T testing a new lot of 4895 powder. The bullet was the 311466 in the .308W.

The RPM of that 311466 load was 144,400 which is at the ragged edge of the RPM threshold for a 12” twist barrel. The first 5 shots of that group went into 1.1 moa and the first 10 shots of that group went into 1.9 moa. If I drop the velocity down to around 2250 fps with a RPM of 135,000 the 10 shot accuracy is usually around 1.5 moa.

Conversely, in the 14” Palma barrel in .308W with the same powder the other day I shot a 10 shot group of the GB 311041 into a 2.1 moa group at 2455 fps. The RPM of that load was only 126,300 which is well within the RPM threshold. Considering those 311041s were from a 6 cavity mould and of bore riding design the accuracy at that velocity shows what controlling the RPMs can do.

If that doesn’t answer your question then please ask for clarification.

Larry Gibson

[Larry Gibson]

Post above was too long to include the photo also so here it is.

Larry Gibson

[Doc Highwall]

Larry, what are you using the lap top for?

[Larry Gibson]

Larry, what are you using the lap top for?

Doc

The laptop is acutally siiting on top of the Oehler M43. The screens and the strain gauge are connected to the M43 which does its thing and then it feeds it to the program in the laptop where the firearm data, test conditions and load data are input. It then shows and can print out a data sheet as shown below. I keep printouts of all my tests, makes for good record keeping of data. I also make some written notes on the printout depending on the test. Note I also lay the test target over the printout and trace the bullet holes and record the group size ctc.

Larry Gibson

[nicholst55]

Larry and others: Thanks for the excellent info! I had hoped to be able to stand a reasonable chance of doing this with a rifle/barrel combo that I already own. I honestly believe that I'm going to need a 14" twist barrel for this project to stand a realistic chance of success.

I hope to be able to consistently shoot 3" 10-shot groups at 100 yards, once I develop a good load.

I guess this project is a good excuse to either rebarrel a rifle or else to build anohter one - like I really need another rifle!

[Bret4207]

HOLY CRAP LAR! That post put a whole lot of what I've been thinking for years into one spot. Outstanding post! That deserves to be a sticky. Well done sir, I'm impressed!

[Larry Gibson]

Thanks Bret.

I think many of us have been saying bits and pieces on this subject for some time. For some reason I just got started and couldn't stop with just a partial answer this time.

I've no idea how or who makes it into a "sticky"(?).

Larry Gibson

[captaint]

Man, I just went on ahead & printed this thread!!! Great stuff... Mike

[BOOM BOOM]

NICE POST LARRY,
I also disagreed with the general norm of the 3/5 shot group crowd.
I shoot 10 shot groups w/ rifle J or Pb bullets.
With revolvers I shoot 2 cylinders full- usually 12 shots. I believe this to show the gun/loads real accuracy. To shoot a partial cylinder full is a joke in my mind.

[Larry Gibson]

Boom Bomm

We are in agreement.

Larry Gibson

[StarMetal]

I'm not going to start a pissing match here. Just gonna say if you can't get a bore rider to shoot then you don't know how to do it. What do you think I shoot in my 6.5 Grendel with an 8 twist? And that 70 grain bullet I posted a pic of in the other thread on velocity and rpm is a bore rider. Both shoot most excellent.

Joe