H4895 in M96!

[dualsport]

Larry, I'm interested in the coming report you mentioned above re. the over sized CM. If I understood that right you are working with the CM? It's a sexy beast.

[Larry Gibson]

Already posted; http://castboolits.gunloads.com/show...Cruise-Missile

Larry Gibson

[andym79]

Well if I don't get what I hope for on Saturday I was going to give Unique a go. Have called around all the gunshops in my city Alliant powder is out of stock here with a three month back order. So no Red Dot, Green Dot, Unique etc. It seems I am now only able to buy ADI (Hodgdon) powders!

Does anyone use any of these powders in the 6.5 X 55.

(AS30N) Hodgdon Clays
(AS50N) Hodgdon International
(AP70N) Hodgdon Universal

[Larry Gibson]

I suggest the Clays and use the starting load suggested for Bullseye and work up slowly to 1200 - 1400 fps.

Larry Gibson

[andym79]

Well once I got chance, and the Lever fever didn't have me in its grasp (I find it hard to want to shoot bolts when I have such beautiful levers that beg to be shot); I finally after weeks of threatening to, took the Mauser out again and shot 2 10 shoot groups at 100 yards. The load was H4198 15 grains and 16 grains, the 15 grain load was the winner by around 1/2"!

I was happy with the load for 100 yard shooting (2 1/2" 10 shot group), it certainly would be in the kill zone for medium sized game!



I still don't think this load is 3 MOA compatible at 300 yards! But next time I go to the range with the M96 I am going to take it out to 200 and see what I get!

[sisterjim]

I'm shooting a GC 266454 100 grain loverin style ACWW/Pb 75:25. I am getting 2" groups at 100 yards with AP100. I'd like to try a heavier boolit so I can get a bit more powder in the 6.5x57R case (equivalent capacity, twist rate and ballistics as Swede) for same velocity. Also going to give 2205 a try in 16-19gr. You want to trade some of the PB 150 grainers for some 100 grainers. I also have a 266455 sc GC mold that I haven't got round to casting.

[sisterjim]

I rethunk my sample set for loading and went 14.5-16.5 grains 2205 (4227). The best groups were 15.5 and 16.5. The 16 group had a flyer, high left. I reckon I had a banana from bumping nose too early in sizer. Going to load .2 and .4 +/- 15.5 and shoot out to 100. Not wishing to hijack the thread but does anybody have any idea how fast this 104 grain boolit is travelling? Thanks JIM

[Love Life]

I like the lack of vertical in the 16.5 gr group.

[sisterjim]

I was shooting off a greasy fallen tree and kneeling in the hole where the root ball had been torn out the ground. The air was calm but the forecast shower was imminent. I didn't leave enough time between shots to allow barrel to cool as it would when hunting. The intervals decreased as the powder charge increased and the raindrops began to fall. The lowest shots on all the groups were the first ones. Subsequent shots probably 15 seconds apart are higher. The rifle is the lower part of a German O/U combination and I figure target shooting isn't going to be it's forte. The stringing is something that I am aware of but not sure if this would be the expected effect as the barrel expands below the cold 12 gauge tube. I won't rule out the 16.5 group in my testing but 15.5gr is easier on the ear and I'd like to ditch the GC if possible and get a multi cavity mold for plain base. I probably shoot 2000 of these each year and expect to increase this figure by as much again. The cost of GC doesn't bother me but I'd prefer to pan lube for convenience.

[andym79]

H4895 25 gns 26 gns 27 gns 28 gns
1 1/2" 1 11/16" 2 5/8" 4"
1900fps 1970fps 2025fps 2100fps

I had to give H4895 ago just to see what could be achieved (without the advise I recieved from Larry Gibson and others, I suspect that 1800 would have been closer to the maximum velocity with good accuracy). I haven't given up on it 100% but its time to move to the next slower powder.

I was happy with 25 and 26 grains and got near the 2K I want to exceed.

The 28 grains at 4" at 100 yards will surely not get me were I need to be at 300 yards!

Stay tuned for Varget and H4350 experimentation!

[Larry Gibson]

andyM79

Excuse me but I am a little confused by your remark of; "(despite what Larry Gibson and others had told me about what could and could not be achieved, indeed without advise, I suspect that 1800 would have been closer to the maximum velocity with good accuracy).

What I said was; "4198 is a good powder as are 2400, 4227,4759 and 5744. None will give the load density you want though and the Dacron filler will be beneficial. Rl7, 3031 and 4895 will also work with the Dacron filler but again will not give the load density you're looking for." You were asking for load density of 60%+ so a filler wouldn't have to be used and 2100 fps for 300 yard/meter shooting. If there is any confusion between us it is perhaps because you were considering “load density” as related to a maximum manual load of powder. “Load density” to me and most refers to the case capacity to the base of the case neck or bullet as 100% load density. Thus we were both correct; you did achieve 60%+ load density based on the max manual load. However, based on the case capacity you did not.

I do notbelieve I told you wouldn't get accuracy at the level you did (1900 & 1970fps). Many of us do get comparable accuracy in the 1800 fps range with M36 rifles and with a M96 into the 1900 fps range because the longer barrel gives better velocity at the same psi. Some maintain accuracy into the 1900 fps with M36s with their shorter barrels but it takes more than just casual casting and reloading techniques. I think if you read that thread I also posted on my HV tests you'll find I made almost 2100 fps with about 2 moa using 26 gr ofH4895 with a M36. With 25 gr I run very close to 2030 fps and 1 1/2 moawith 10 shots. That load also holds up with linear expansion at 200yards. However, neither load is 60% load density let alone exceedingit. At 24 -25 gr (my standard load) the velocity drops into the 1800+ to 1900+ fps range and accuracy is very much like your own 1st two loads. However, with your M96 and it’s longer barrel you can achieve higher velocity at the same pressure o rthe same velocity at a lower pressure. Both of which are good.

Your first 2 loads show excellent accuracy and potential. I suggest you test those loads at 200 yard/meters for linear expansion. If the expansion stays linear then you know with a slower powder and less psi at the same velocity that load should also stay linear and be a good load. However, with the suggested slower burning powders you just might get to 2100 fps with decent accuracy. Varget may or may not show an improvement as in some cases it doesn’t burn that efficiently at lower psi. Sometimes it does, sometimes it doesn’t. Only one way to know with your bullet and rifle. The H4350 should be much better and H4831SC perhaps a bit better. Again, only proper testing will tell. With those you will have 60%+ load density.

Larry Gibson

[andym79]

Larry, I meant no offence, it was very poorly worded! I have ammended it as I feel its was a poor expression of what I was trying to say. You advised me about thinks like bullet type, alloy hardness, lube, fillers etc in other posts and PMs. Indeed it was mostly a reference to the suggestion that I use a 4350 powder and I am yet to try that.

What I was trying to say was without advise on those things and others I would have probably lost accuracy at 1800fps with that same load, for a start I was using the Saeco mold with plain alox previously!

[andym79]

andyM79

Your first 2 loads show excellent accuracy and potential. I suggest you test those loads at 200 yard/meters for linear expansion. If the expansion stays linear then you know with a slower powder and less psi at the same velocity that load should also stay linear and be a good load. However, with the suggested slower burning powders you just might get to 2100 fps with decent accuracy. Varget may or may not show an improvement as in some cases it doesn’t burn that efficiently at lower psi. Sometimes it does, sometimes it doesn’t. Only one way to know with your bullet and rifle. The H4350 should be much better and H4831SC perhaps a bit better. Again, only proper testing will tell. With those you will have 60%+ load density.

Larry Gibson

I think trying the first two loads at 200 yards would be a very good idea.

I might limit how many loads I load up using Varget, as I think it is unlikely to get me more velocity accuratley than the H4895!

[frnkeore]

Hmmmm.......

With 25 gr I run very close to 2030 fps and 1 1/2 moawith 10 shots. That load also holds up with linear expansion at 200yards.

180,740 rpm and still linear? Other people do that, too with even better accuracy, Right?

So again, what is the "threshold" RPM? Threshold...... is that something that I can find anyplace else? Or do we just have your word for it and unscientific testing?

Do you have to have reloading skills that most people don't/can't have to find accuracy above 12 - 140,000 rpm ("push it up")?

I've been very confused about this, for a very long time. I see a lot of people getting accuracy well above 140K but, 140K should be where things start falling apart but, it doesn't seem that way. It seems that excellent, even superior accuracy can be had well above 140K.

Now regarding linear groups with cast bullets........ Where can I find in writing, that the ratio is 2 to 1 groups at 100 and 200 yards with cast bullets?

I found a written source that says, in a study, done excusively with cast bullets and over close to 1000 or more groups, that the average is approx 2.8 to 1. I think given a little positive leeway (rounded up), I think I would consider 3 to 1 as proof of reliable results.

Frank

[Larry Gibson]

Frank

We've been aware of your confusion for sometime. I have explained it over and over to you ad nauseum. I will explain it again. Perhaps you will understand it this time?

Part of your confusion is your consistent expectation the RPM Threshold is a"limit' in the 120-140,000 RPM range......IT IS NOT A LIMIT. The reason it is called a “threshold” is because if you cross it with a certain combination of components accuracy as in group size goes south......sometimes rapidly and sometimes more slowly. That RPM Threshold with regular cast bulletsof the common ternary alloy is generally between 120-140,000 RPM. However, through judicious casting and reloading you can push that threshold up. How much depends on how judicious the casting and reloading is as in improving technique, using a stronger alloy, a better designed bullet, a slow burning powder, weight and visual bullet sorting, etc. Depending on the rifle,the barrel twist, the barrel length and all the above you can push (move up if you can’t understand “push”) up to a higher RPM. However, there will still be a threshold just at the higher RPM. Once you cross it at that higher RPM level accuracy goes south again.

You can also lower the RPM threshold by using inappropriately poor or soft alloys, poorly designed bullets, fast burning powders, and through sloppy casting and reloading, etc.

In the case of the 6.5 Swede at 2050 fps or so and maintaining linear group dispersion if you read my 6.5 Swede thread you will see the hoops I jumped through to push the RPM Threshold up to just over that velocity. No it isn’t easy and it takes meticulous attention to detail (anal attentiveness as some call it) but it can be done.

As to your confusion regarding linear expansion; you have a habit of researching CBA match results and comparing those results using a decimal point figure to the tenth. As I have told you before linear expansion comparison of 100, 200 and 300 yard groups are not expected to be measured to the nearest .001” as in CBA matches ans
d sometimes not even to the inch. Let’s say you go out on one day and shoot a 10 shot group at 100 yards of 1.5” and then a 10 shot group at 200 yards of 2.5”. On the next day you shoot the same load/rifle with a 100 yard group of 2”and a 200 yard group of 4.5” and on the next day you go out and shoot a 1.9” group at 100 yards and a 5.1” group at 200 yards. Those groups with the same load/rifle are all within expected variation of linear expansion. However, if you went out with a load and it shot 2.5” at 100 yards and then 8.9” at 200 yards you could probably bet that is non-linear expansion of the groups as it is way outside any expected variation. What should be self evident to you, as it isto everyone else, is that linear expansion of groups does not mean the groups have to be exactly twice as large to the .001 or even to the .1” at 200 yards as they were at 100 yards.

As an example the targets pictured show consecutive groups fired at 100, 200 and 300 yards with the 2600+ fps load out of my Palma rifle. There was a 5 mph +/- wind comingout of 9 o’clock and I did not correct for it. Note the groups at 200 and 300 yards are not EXACTLTY 2 and 3 times as large as the 100 yard group. They are not expected to be because we seldom shoot all our groups exactly the same size. There is an expected +/- of group sizes. The targets show excellent linear expansion.

The next pictures show a test of linear expansion with the same bullet at 50, 100 and 200 yards; one load under the RPM Threshold and one load over the RPM threshold. Should be obvious what non -linear expansion is.

Larry Gibson

Attachment 111276Attachment 111280Attachment 111279Attachment 111277

[MBTcustom]

Larry, I get the RPMTH. Its just how fast you can spin with a certain load (brass, primer, powder, alloy, boolit, lube etc etc etc.) No problem.
I would like you to expound on "sloppy reloading techniques".
In your opinion, what are the main things we can do at the bench to shoot faster?
You choice of words: "Sloppy" seems to convey more than just going and buying a Star lubesizer and matchgrade dies.
I mean, reloading dies are pretty simple tools. You make vertical adjustments, then you use them. It doesn't seem to matter whether you ram the cartridges in the dies or push them lovingly through the stoke, pinky in the air.....or does it?

What are we doing at the bench that could be detrimental to our group size other than seating depth?

[frnkeore]

So, it is turning out that it's not really the RPM that is effecting the accuracy of the cast bullet in the <140K RPM range but, how well the bullet is cast, how well it's loaded and how well the chamber of the rifle is able to align the bullet, before it starts to spin?

Range	Velocity	Impact	Drop	ToF	Energy	Drift
0	2600	-1.5	0	0	2252	0
100	2251	2.72	3.08	0.13	1688	0.97
200	1936	0	13.11	0.27	1248	3.38
300	1652	-12.1	32.51	0.44	909	7.84

Note the wind drift for a 5 MPH wind drift, using the 311466 (BC .25), 3 1/2 times the the 100 yd drift @ 200. Do we divide the 200 and 300 yard groups by a factor of the wind drift, to get the "linear" thing?

Real people shoot in the real conditions.

Frank

[PAT303]

And another 6.5 thread goes off the rails. Pat

[andym79]

Guys this thread is not supposed to be a discussion about the RPM threshold, whatever your opinion! Discussing it here is fine, but lets just discuss it relatively to the thread!

In my opinion it is one factor that plays a role in effecting accuracy!

The discussion is meant to be on the virtues or lack thereof when using H4895 powder in the 6.5X55.

Any comments with regard to powder selection and loads for this case are welcome.

Here I detract myself.

I was reading through some bench rest stuff. Its not my area of interest, but it raised an important issue.

Barrel harmonics, the theory basically states that the vibration within the barrel means there are multiple sweet spots for the projectile to leave the muzzle. These sweet spots are related to barrel time and timing the exit around vibrations.

In theory then there is more than one load of a powder which can lead to accurate groups.

I believe experienced this phenomenom when using H4198 in the 6.5x55, this was before I had read a thing about optimum barrel time.

I worked up through some loads and accuracy started going south. I had another three loads in the box, each set 1/2 grain higher than the previous. The first load gave the same sort of group as when accuracy went downhill, the second two however resulted in groups better than the previous two, close infact to the group fired with 1 1/2 groups less.

What other than barrel harmonics explains good-good-bad-bad-good-good groups (apart from the shooter of course)?

[PAT303]

I have found the same thing with the swede as well as my LE's,I think it's one of the many problems we face,I always shoot loads a grain or two above the point that accuracy went to pot for this very reason.I'll be shooting some AR2217 loads this weekend with fillers if the weather holds out,nothing but rain now. Pat