.375 H&H, IMR4895, reduced load, loading strategies to get the most accuracy

[Whiterabbit]

Need some loading advice from the great people here.

So, I'm actually shooting the speer jacketed, and frankly in a 375 Ruger. BUT, a few things:

1. My node is at 66gr, which matches other people's ideal 375H&H load.
2. I think more people here have 375 H&H experience and it seems to directly apply to 375R.
3. I think cast booliteers have much more experience with IMR4895, with downloading, with downloading 375H&H with IMR4895, and that I'll get much better info from the brain trust of Cast Boolits than anywhere else.

So, here it is:

66gr of IMR4895 (seems to be more available than H4895) is doing really good for me so far. But accuracy is double what I want, and more than double what the gun is capable of in ideal situations. Normally, I start messing with OAL till things tighten up, but I'm worried that's not the right answer here. I believe this because I'm usually developing loads at or near 100% case capacity, and since I'm floating around 2380 fps with a reduced load, OAL is not going to appreciably change empty space in the case.

SO, known that cast booliteers are the masters of playing with light loads in big cases, What are the strategies you would recommend for this case, with the goal of decreasing group size?

- try a light dacron filler to take up some case space, test OAL changes
- stuff the case full of dacron so that powder is practically crushed, test OAL changes
- fix the OAL where it is, and try varying amounts of dacron filler from light to heavy, see what it does
- forget the filler because it's IMR4895 (you tell me, I don't know much about this powder) and just go straight to OAL as-is
- you're way of base Steve, what you need to try is _____________ (crimp, primer, different powder, or?)

Anyways, tell me about IMR4895 in reduced loads, what kind of tuning do you do with them when you are looking to make tweaks?







I am making a "cheap plinker" load in my 375 Ruger. It should be like a fat version of a 30-06 and match plains game ballistics of yester-year. While at the same time be great for deer/pig/black bear/elk/small motor vehicles/rabid wolverines/whatever, and even some medium range steel shooting when using a bipod and suitable scope.. I'm almost there!

[nelsonted1]

I shoot a Shetland pony sized .376 steyr. It is at full power, more than my crippled neck can bear (except when showing off��). I use the minimum 3031 load under 235 gr speer. But mostly 860, 872 or 5010 with 3 grains of 3031 to blow the unburned grains out under a 270 grain Lyman bullet. The rifle is.a dandy little.carbine if it was.a 7-08 or .260 but 7 lb or so in a .375 is brutal.
Now to an important point: don't pack a case with dacron. A long time.ago on here there was.a.lot.of.barking about case full of filler packing into a hard.ball when fired. 4895 shouldn't need a.filler. Me, personally, am afraid of filler in rifle cases. That's me cause I'm chicken. So some research there's lots of it.
Ted
I want your rifle badly.

[Walks]

I think you may be confusing IMR4895 with H4895, for Reduced Loads.

When I had a .375H&H I used IMR3031 for full power JSP loads and H4895 for reduced loads for JSP and either H4895 or SR4759 for Cast Lead loads.

You CAN NOT use IMR4895 in place of H4895 !!!
I Repeat DO NOT Substitute IMR4895 for H4895 !!!

No filler is required for H4895 reduced loads.
Go to the Hodgdon Website and check it out for yourself.

[Larry Gibson]

Whiterabbit

A bit confusing as you don't say what Speer bullet you are using with the 66 gr IMR4895 load?

Also, are you asking about reduced loads of IMR4895 with a jacketed bullet or a cast bullet?

FYI; IMR4895 works just as well with reduced loads as does H4895. I've been using both for 50+ years and have been measuring pressures of many reduced loads in numerous cartridges with both for 10+ years w/o any indication of pressure problems.

As to the use of a Dacron filler I recommend it for use with reduced loads of either 4895 under cast bullets in the 375 H&H. I use 49 gr IMR4895 with the Dacron filler under the 377449 for 2200 fps out of my 12" twist M70.

I do not use the Dacron filler with jacketed bullets. I found 65 gr IMR4895 under the 270 gr Hornady or 68 gr under the 285 Speer (no longer available) were usable loads but not as accurate as Varget with the same bullets. I use AA4350 under the Hornady 300 gr bullets or the Woodleigh 350s for best velocity/accuracy.

Having measured the pressure of thousands of loads in various cartridges with a Dacron filler under cast bullets I've found absolutely no indication of any problem. I use a Dacron filler in numerous cartridges where appropriate and the use of such does not scare me in the slightest. To he contrary, I have the utmost confidence in improved performance with the use. There is a difference between a "filler" and a "wad" which I explain in the "sticky" on the subject found in this forum site. Like many things we do in reloading the use of a filler can be quite safe and rewarding in performance but if used improperly it can also be a hazard. I've no qualms with those who choose not to use a Dacron filler as that's their choice. I choose to use the Dacron filler where applicable such as with IMR4895 under the 377449 cast bullet.

[Whiterabbit]

Oops, you are right! I’m using the 235gr speer bullet. It is the best mix of low price and easily available. Of course, I’d like to avoid using dacron if possible just to minimize variability, but will go there if needed. But it sounds like generally speaking, 4895 is not a filler-required powder, though not uncommon.

At least, that’s what I’m hearing.

Anything I should check besides OAL? The throat is long enough that the leade will be a jump no matter what I do, not unlike most older rifles, in my experience. So it will be a balance of empty case space (I’m sitting between 85-95% case fill right now) and jump to the lands no matter what.

[Whiterabbit]

Correction, checking quickload, it’s 79% case fill. 35.6ksi, and 93.6% burn amount. I notice there is no kernels in the barrel after firing. Quickload says 2393 fps, my 5 rd average was about 2385, not bad.

What do you guys usually use to determine if dacron is needed or not? When you use it, is it just trial and error for you, or do you try it because you have erratic velocities, unburned powder, or something else?

[Larry Gibson]

Once again, up front, I do not recommend using a Dacron filler or any filler with a jacketed bullet load. I suggest you read my post #2 in this thread as to my recommendations for the use of a dacron filler; http://castboolits.gunloads.com/show...use-of-fillers

"My node is at 66gr, which matches other people's ideal 375H&H load."

I assume by "node" you mean accuracy load(?) but I have no idea where you come up with that? The starting load for the Speer 230 gr bullet using IMR4895 in the 375 H&H is usually 66 gr. My older manual that I developed my 375 H&H loads from lists 73 gr as a max load. I found the best accuracy with the Speer bullet and IMR4895 came at 72 gr for use in my M70. However, that bullet never did, for me anyway, give the best accuracy in my rifle. For a lighter weight bullet my rifle favored the 225 gr Hornady SP but really has always shot the best with 250 gr or heavier bullets. I suggest with your Ruger 375 you work up to 73 gr IMR4895 with no filler and see if accuracy improves.

[Whiterabbit]

I’m looking for a load at or under 2400 fps, i’m told a speer going faster makes a mess of an animal. I got 66 from the internet, but worked up loads from 64 to 69 grains. 66 had a fabulous ES/SD and the best group size. But group is 1.5 moa 5 rounds, i want to improve that a little.

I will absolutely take your advice, no filler for a jacketed bullet. I still need to figure out what to do to improve group size. Normally, i seat the bullet deeper to get to 100% case fill and that does it for 99% of my loads, tightens everything right up. But Im already seated to the ojive, so no luck there. I’ll try longer just cause, but looking for strategies to affect group size without changing powder charge.

Only other way to get to 100% case fill at 2400 fps is to switch powder. But I always prefer not to do that if i dont have to. Velocity uniformity tells me IMR4895 seems to be ok at 79% case fill...

[Larry Gibson]

Yes, the 235 gr Speer can be a very destructive bullet at higher impact velocity. Since you want to keep velocities down at 2400 fps or less why don't you consider a cast bullet? After all this really is a cast bullet forum.

However, going to a slower burning powder for better load density may give more inconsistent burn because of the low mass (for caliber) of the 235 gr bullet. I don't know because, as mentioned earlier I gave up on the Speer bullet early on. I would suggest a bit faster more easily ignited powder such as 3031, RL7, H4198 or even 5744. I've not used those in the 375 H&H but in other cartridges with reduced loads using jacketed bullets they work well enough.

Still, I doubt you will get the accuracy you want consistently as there's probably just too much working against it with the large case and light for caliber bullet. Again I quit using the lighter weight bullets because the accuracy was there only at top end and that load impacted far out of the norm for all the other loads. Here is 3 shots each from 4 different loads at 100 yards from my M70;

Attachment 248222

Sometimes we must accept the fact that what we want isn't going to be feasible [in your case, excellent accuracy with the Speer 235 gr bullet at low end velocity] and go with what really works. If you really want to use the 235 gr Speers at 2400 fps or less then the accuracy you get with your 4895 load may be all it's going to be. However, I suggest a change of powder to a slightly quicker burning one as that may work. You won't know till you try.

[Whiterabbit]

I had to give up on a cast bullet already, I tried the NOE 379-284 without success. I tried it with IMR4198 and bluedot. 4198 was all over the place so I didn’t even bother to calculate more results. 1400’s to 1800’s fps. Can’t nail it down better than that cause we are talking triple digit ES and several inches group size. Bluedot fared much better, with 1320 and 1410 fps having reasonable SD but concerning accuracy. Accuracy fell off after 1400 fps.

I doubted my ability to get it performing well above 1600-1800 with a gas check, and at those velocities I doubted the purpose of a 375 Ruger, as the power is in the handgun range (at least at 1400), not just the 30-06 range (which is where I am with the 235gr bullet and ~2400 fps).

For cast, I could try the 376-329, but I think that’s about as far as I’m gonna get in weight. I expect with my alloy (hardball) and a gas check I’ll be again limited to maybe 1600 fps. Will have to sell my barely used 284gr mold first.

I worry more about switching between cast and jacketed though after a recent BFR study where I destroyed the accuracy of a WONDERFULLY shooting BFR by shooting some barnes bullets in it. Back to my awesome cast load and couldn’t hit the broad side of a barn. I’m still trying to clean out the copper and re-season the barrel, and I’ll never shoot copper in it again, ever. That has me nervous about developing/shooting cast in the ruger, since the “expensive” load is a 350gr sierra match king with a stiff charge of H4350. The future may see more CPX4 stuff with solids etc.

Anyways, I appreciate all the advice, I am carefully considering all of it. You may be right about the 4198 suggestion and I’m going to think about that a bit more. Sounds like the general thinking though is that if the desired accuracy isn’t there right away when charge testing, it’s not worth pursuing once the ideal charge is found.

[Larry Gibson]

Okay, let's talk cast bullets. First off that NOE bullet is a PB'd(?) bullet and just isn't going to perform well above 1500 +/- fps no matter what you do. If you want accuracy and performance above that then a GC'd cast bullet is needed. I always have some copper wash in my 375s barrel as is shoot both cast and jacketed. I know it's heresy here but I've not found the copper wash (just slight copper coloring in the bore....not to be confused with severe copper fouling) to be detrimental to accuracy at all. I have to agree with M.V. that unless you have a rifle really capable of superb accuracy and are competing in CBA matches I wouldn't worry about having to have scrupulously clean barrel before shooting cast. I have shot jacketed and cast intermittently during the same shooting session with no decrease in accuracy with either.

I suggest the Lyman 375449 bullet. I cast mine out of COWWs +2% tin and WQ (heat treat) them right out of the mould. That gives them a BHN of 17 - 18. Mine drop right at .377 which is what I size and GC (Hornady) them at in a Lyman 450 using 2400+ lube.

I NS the Winchester fire formed cases and expand the neck with a Lyman M-die. WLR primers are most often used. I have 2 loads I use; one is a heavier recoiling "dangerous game" load I use for practice and the other is a milder "fun" load. The heavier load would/could/has been used for hunting also but the milder load would certainly thump deer or pigs out to any reasonable range.

The first load is with 49 gr IMR4895 with a Dacron filler. It runs right at 2200 fps and has given several 2 moa groups (10 shots) at 100 yards and holds nicely to 200 yards. I have pushed it up to 2400+ fps but accuracy runs 3 -4 moa although I do sometimes use that load for duplicating the recoil in close range multiple shot practice, usually with friends (one also has a M70 375 H&H and the other has a M70 404 Jeffry). That "practice" is with 12" bulls at 40 and 30 yards and 6" bulls at 20 and 10 yards in a slight angle from the shooter. The M70 has 3 in the mag, one up the spout and is at a standing shouldered ready position. On command one shot at each target (just hit the bull) from 50 to 20 yards as quick as possible simulating a charging animal. We usually shoot 3 to 5 "runs" apiece with and run with a miss not counting. Fastest time has bragging rights over the sundowner and cigar after shooting is done......

Anyways the 49 gr load of 4895 w/Dacron filler works well with the 375449 cast bullet. I have also used H4895 with equally great results.

The milder load which I consider my "baboon and lessor game" load is with 36 gr of AA5744 under the 375449 with no Dacron filler. It runs 1860 fps and is also a 2 moa load (10 shots).

You might give the 375449 a try.

My M70 three six bits......

Attachment 248228Attachment 248229

[charlie b]

If you are still trying to remove copper get som KG12. It will get all the copper out with less fuss than most.

For reduced loads I tend to go with heavier bullets as well. But, you can find the right mix for reduced loads if you juggle powder, load and bullet weight. I've been using IMR4198 and IMR4895 for those jobs with Blue Dot for 'gallery' loads (~1000fps).

My limited shooting with reduced loads has shown that they can be very sensitive to changes in charge weight. Sometimes a 1 or 2gn change in powder will turn a tack driver into a 'hope I hit the paper' load.

I understand wanting cheap bullets (which is why I cast) but, like Larry said, sometimes you just can't get what you want.

Sent from my SM-P580 using Tapatalk

[rhouser]

If you are looking for a reduced load with the speer, check out the documented trail boss load on this link: https://imrpowder.com/wp-content/upl...-loads-r_p.pdf This is from the factory so no real safety questions.

My 2 cents.

v/r rch