25-06 Pressure Signs

[SlowFuse]

Seeking info on a load I used yesterday afternoon. Here's the specs:

Sierra GK 117 grain
Prvi (PPU) Brass
Winchester LR Primer
Hodgdon Hybrid 100V
Rifle used was a Weatherby Vanguard

I started with the minimum load (per Hodgdon data for the 117 gr Hdy SPBT) of 46 grains of H100V a few weeks back. I checked Speer for cross ref and they do not list my powder. I have been working up in increments to get a feel of what works for this rifle. The loads related to this question were loaded at 48.8 grains and an OAL of 3.2in. I did my usual 10 rounds of Prvi factory ammo (really just shoot it for the brass!) Then started doing 5 shot groups of my loads. I shot the same load prior to this one with the only exception being an even 48.0 grains of 100V. No problems there in the slightest. I move up to the 48.8 not thinking much of the jump in powder (Hodgdon states max is 50.5 grains) and have problems. Flattened primers and what I assumed was a sticky bolt. Bolt gave resistance on the upsweep before pulling it back to eject spent shell. This is my first experience with this. So, opinions/constructive criticism welcome, could I have reached a max for this rifle even though I'm 1.7 grains under max? I understand every rifles tolerances are different, but i've been able to work up to max on all of my other experiences. I appreciate any replies in advance.

 

[rcmodel]

Prvi (PPU) Brass may be thicker (have less capacity) then the Remington cases Hodgdon used in testing.

You are also using a different bullet then Hodgdon used.

Those two things could explain it.

rc

 

[TNBilly]

Every rifle is an individual, every combination of components is unique to a point. It (your rifle) is telling you you've already gone past the level it'll safely tolerate by the stiff bolt. If you're to use the same components then back it back down to 48 grs. and work back up. IMHO .8 gr is too big a jump when you're getting near the top of the load. I usually load in 4-5 tenths increments initially searching for the accuracy sweet spot, not the hottest load the weapon will tolerate usually. Just FYI and a guess from my experience I've had the best luck with H414 or H4831 (depending on bullet weight) and American brass. I really have liked the H100v powder in other loadings, just haven't tried it myself in 25/06.

 

[Clark]

I would back off 4% [for extreme powders] powder charge from the threshold of stiff bolt lift or primer pockets getting loose in a few shots.

Stiff bolt lift does not count if the brass got neck sized a bunch of times in a row. The stiff bolt lift as a pressure sign should be if the shoulder was pushed back .001". Then I know for sure.

If the brass is going to have loose primer pockets in a few shots, the extractor groove all the way around will have an increase [before and after firing] on the dial caliper in at least one spot on the first shot.

If I go to the range with 46, 47, 48, 49, 50, 51, 52, and 53 gr, and the dial caliper picks up a .001" increase in the extractor groove at 50gr, I stop the work up.
I go home and load 49.1, 49.2, 49.3, 49.4, 49.5, 49.6, 49.7, 49.8, 49.9, and 50 gr.
Then I return to the range.
In the work up, if I see a .0005 change or more from 49.5 and on up, I go home and load my ammo at 49.4 - 4% = 47.4 gr.
I load up 50 rounds of that.
Then I go see how well I can shoot it at long range.

The reduction percentage for RE17 is much bigger than 4%.

 

[SlowFuse]

Thanks for all of the replies and suggestions.

I plan to go back to the 48.0 grain load. It was better than expected accuracy wise so I'm content with sticking with the nice even number. I only got to round 2 of the 48.8 gr batch and decided it wasn't worth continuing. The remainder got pulled and dumped today.

TNBilly suggests American brass. I've always had this theory myself, but have found the PPU to be as good as the Rem brass I load for this caliber. But, what RC suggested about case thickness hadn't occured to me, so I will be comparing a new pc of PPU to Rem brass. Have any of you heard bad things about this brass particularly? I see mostly good reviews on it. My experience has been good so far, no loose primer pockets or split necks. I always do the "paper clip" test for signs of case seperation.

Clark, I have never heard the case of numerous neck sizings causing an excessively stiff bolt, so I will keep that in mind. I'm guessing because the cartridge has such a snug fit in the chamber? This particular round was twice fired brass, this being the third firing if I had completed the lot, but it was neck sized. All of my 25-06 brass is, this Wby is the only 25-06 I currently shoot.

 

[NCsmitty]

It's been my experience that Prvi-Partizan (PPU) brass is the equal of most standard American brass, and should be fine to use. I don't know how the capacity compares to American brass, but I have a supply of PPU SP ammo for my Russian 7.62x54R. I personally do not mix my brass, and prefer to use one brand of brass for each caliber. Most of my brass is Remington, but I use Lapua brass in my 6.5x55 because it is dimensioned closer to original Swedish chamber size.

I believe Clark was talking about work hardening your brass from sizing it numerous times, but 3 loadings usually is not enough to create this condition unless the brass was not annealed properly to start. Not likely an issue at this time.

Your assumed pressure spikes may just indicate that your rifle has a tight chamber, and will not take maximum listed loads of H 100V. Make sure your brass meets proper trim length. If this is a new rifle, make sure that the barrel is not suffering a buildup of copper in the throat, and through the rifling.
You'll need to check and see if this problem occurs should you change powders, or if it's an anomaly that is happening with just this lot of powder.

I'm curious how the factory ammo reacted for bolt lift and accuracy?


NCsmitty

 

[jim147]

I like my PPU brass but I've never checked it for volume.

As rc pointed out you changed a couple of components. I've seen the bearing surface of the bullet make a surprising difference in what a max load is.

We had the hottest day ever on record here today. Unless your someplace I wish I was, heat does have an effect on pressure. Even with a Hodgdon powder.

jim

 

[tightgroup tiger]

Your assumed pressure spikes may just indicate that your rifle has a tight chamber,

I agree completely,
I have a 30-06 Browning at home that with 4350, the max load is around 54gr instead of 57 like the books call for.

I has a chamber so undersized that would only chamber 7 of 20 of the only box of factory loads I ever bought for it.

It is also, hands down, the most accurate rifle I have ever owned.

 

[SlowFuse]

NCsmitty I would consider this a new rifle; I bought it towards the end of last year. It has approx 160 rounds through it, which I would think is just barely broken in. I will check for copper buildup. As far as the factory ammo accuracy, the only thing I have ran through it factory wise is the Prvi 90 gr HP. It has decent accuracy. My normal setup has me sitting at about 160yards away. Odd distance, but it’s what works on my property. I usually get around 1.75” groups with this, which I don’t think is bad considering the price of the ammo. Bolt sticking hasn’t been an issue. Same goes for the other handloads i’ve put through it. This particular load that I started the thread on was my first experience with flat primers and sticky bolt, ever. Accuracy with other handloads has been impressive (for me) since I don’t consider myself to be a world class shooter. I’ve gotten groups around an inch at 160yds with my 85 and 100 grain loads. It seems to like the lighter stuff.


Jim it was a hot one! Heat index was 101 degrees, i’m in central AL. On the tight chamber issue, is there an easy way of measuring chamber dimensions? I’m sure there would be some expensive gadgets that could do it, but any tricks? Or is it something you just know from looking at so many different ones?

 

[GooseGestapo]

IT'S THE POWDER...

I tried the H100V in my .257Roberts and got the same results.

Book listed charge is 48.0gr for 3,200fps and 45,000cup. This should have raised my suspicions already..... these numbers "don't compute", but I assumed I was "nobody" and shouldn't question Hodgdon's "numbers"...

I started at 46.0gr and blew a primer!!! Not just hard extraction and cratered primer.... But I WAS using Federal brass which is even heavier than PPU brass, which is very similar to Remington and Frontier brass btw.....

I reduced to 44.0gr and got "normal" pressures accompanied by "normal" speeds of ~2,900fps. Or, about like a similar charge of H380.....

I fertilized the Azalea's with the remainder H100V...... It was a "bad" batch, I assumed....

For the .25/06 and 117/120gr bullets, I suggest you start with H4831SC, and later some IMR7828.
You'll find a good load with one of these...

 

[SlowFuse]

Interesting info goose. So it could be possible that this powder is hotter than Hodg is letting on... That combined with the fact that the brass could have a lower cap. I've gotten good insight so far, looks like I need to do some investigating. Appreciate the input.

 

[Tolkachi Robotnik]

Micrometer your finished necks.

All good information above. Brass is probably okay but maybe soft and flowing forward. Check with micrometer your neck diameter. Norma brass is the one I have had problems with after just a few shots, but not with 25-06. Clean chamber.

I haven't used the powder but understand it is slow, should be fine enough.

I usually use Surplus 4831 from WWII, and believe it is not getting any spunkier now. I could fill the cases and strike it off and probably have no pressure problems. I have never found any other load as accurate in 25-06 though, than this old powder.

 

[jmr40]

Use and trust your chronograph. If a particular load says 60 gr is a max load and you should be getting 3000 fps with that powder charge, when you reach 3000 fps, that is your max load, in that rifle. If you reach 3000 fps at 58.5 gr, stop. If you get to 60 gr of powder and are only getting 2900 fps, then 60 gr is not a max load in your rifle.

Measuring velocity with a chronograph is the most accurate way we can measure pressure without sophisticated equipment. If you are gettng sticky bolt lift you are WAY over pressure before that shows up.

Some rifles will be much different, as will different cases. You might load 60 gr in a Remington case and have a very safe load getting 2980-3000 fps. Put that same powder charge in a Federal case and you might have an over pressure load getting 3100 fps. Nothing wrong with Federal brass. It just takes less powder to get the same pressure and velocity. If you change brass, you need to back off and work up with that. Might find that 59 gr of powder in a Federal case gives you exactly the same accuracy and velocity as 60 gr in a Remington case.

 

[kludge]

Slow, perchance the cases were not trimmed?

 

[SlowFuse]

I will measure the necks when I compare case volume between the PPU and Rem. Kludge, I did think of this so when I pulled and dumped these rounds I measured. I don't have the notes around but they were in spec. In fact the 2 fired cases that showed pressure signs stretched very little. Great suggestion though. I was afraid that could have been the problem.

I have a list of stuff to look for, not that I will be trying to push this load back to max... I am completely content with the 48.0 load for now. I don't load in the house so its not always convenient to get down there on a daily basis.

 

[41 Mag]

I have tried Hybrid in a couple of loads and found it does react differently than most other powders I have used. In my .243 loads it rocks right along with the published data, however in my .270 it seems to be about a grain or two faster.

I haven't tried it in the 25-06 as I have had such stellar performance from RL-22 I have no desire to look else where. With bullet weights ranging from 110 through 117grs RL-22 has been hands down the top powder not only in my personal rifle but several of my friends rifles as well.

If you decide to try additional loads with other powders put it on your list, I doubt you will be disappointed.

 

[SlowFuse]

Thanks for the info 41 Mag. I have yet to try IMR powders but am definitely open to suggestions. So far I have been in the Hodgdon camp for all of my rifle loads.