7mm-08 non toxic using RS52

[User00040]

Couldn’t agree more if PPU works in your gun youll not find a cheaper way to shoot.
However, I’m firmly of the opinion, that the time will come, probably sooner than later, that it’ll be a requirement, that any food going into the food chain will have to be shot with non lead ammunition, agree or disagree, like it or lump it, it’ll not matter and the price of factory non toxic cartridge is enough to make my eyes water and my wallet squeal.
So working on the principal of the seven P’s ( prior planning and preparation, prevents **** poor performance) I’m going to be ahead of the game.

Plan foiled when the price of bullets (the component bit, not just loaded rounds) starts going over £1 per bullet... which it already has for most makes.

How long before it becomes £5 per shot?

Why bother checking zero and verifying drops at distance when it could cost you £100?

Hope deer dogs become mandatory for all UK stalking, if not, then dog walkers will be finding them for you!

 

[User00040]

Going back to my original post in January, motivated by an impending outing to the Highlands, I've finally found the time to run a load development on the Fox 130gn classic hunters, which I acquired, to develop a non toxic load for the 7mm-08.

Some of the delay was due to waiting for the arrival of some neck turning components as I’d decided to go down that route as a bit of an experiment ( playing about, just fancied seeing if it made much difference) as regards case prep.

So for those that showed interest here are my findings, along with the usual caveats, that this info is from my rifle and shouldn’t be replicated without the usual safe reloading procedures being followed.

Case, new Lapua 7mm-08 once fired, full length sized, bumping the shoulder back by .002”, turned to clean up and uniform the neck, then expanded using a mandrel to give .002” of neck tension.

The Quickload data I’d acquired suggested that 42 grains of RS 52 loaded at 2.800” coal (head to tip), ignited by a BR2 primer, predicts peak pressure of 45647psi out of a possible max pressure of 60191psi, which should achieve a velocity of 2805fps out of a 24”barrel and a propellant burn of 99%.

My rifle has a 20” barrel so realistically you could probably knock 25fps/ inch off that, so I was expecting around about 2700fps.

The first problem I ran into as highlighted by Ed at Edinburgh rifles, the supplier of the Fox bullets, was that because of the shape of the ogive of the bullet, they’d have to be seated quite a bit deeper than usual. So running a seating depth check showed that the bullet was engaging the lands with the bullet seated at COAL 2.697”(head to tip), using that as a datum, I elected to use an initial seating depth of .035” off, as with various loads in the past, I’ve had good success in and around the .030” off area.

I loaded up a range of powder weights, which I’ll give in a table later, from 38gns to 42gns, the first three at .5 grain increments just to verify safe pressures and from 39.2 grains onwards at .2 grain increments.

The principal is to shoot these over a chronograph to observe where at least three adjacent loads, give the least amount of variation in velocity, therefore indicating a load which will ultimately give a low ES, being tolerant to slight variation in load weight. Also if shot at a paper target, classically, you can usually see each shot gradually print higher on the target as the velocity increases, with hopefully, the shots, with the closest velocity, printing closest together on paper ( that’s the theory anyway) and it works more often than not.

The problem was that this first ladder produced a target where the bulk of the shots produced a group of a little over 1 1/2” @ 100m, with the higher velocity loadings, regularly printing lower than higher. The velocity’s achieved ranged from 2682fps from 38grains to 2919fps from 42grains.

I settled on a load of 40.8 grains which gave an average 2862fps and after a bit of messing about with different seating depths showed no improvement and gave a group of just under 3/4” @ 100m.

No pressure signs whatsoever were observed throughout the whole series of loadings.

I’ll try all of this again later with standard cases to see if the prep made any difference and I’ll probably do a better seating depth ladder as well. But this loads good enough to take stalking, so I’ll see how it performs on the beasties.

The main observations.

RS52 yet again shows to be more lively than Quickload predicts, Laurie's absolutely spot on, as per usual.

The Fox bullets appear to give very good accuracy and aren’t very fussy about velocity variation. They need to be seated about 0.150” deeper than the average lead bullets of an equivalent weight (up to the bottom of the last cannelure)

Hopefully they’ll do the business !!!

View attachment 206211

LOAD DEVELOPMENT OCW POWDER TEST
			Date:
RIFLE:	Sako 75
CALIBER:	7mm-08
CASE:	Lapua new
BULLET:	Fox 130gn
SEATING DEPTH:	2.800 oal (2.200)
POWDER:	RS 52
	POWDER WEIGHT	VELOCITY ACHEIVED
1	38	2682
2	38.5	2709
3	39	2737
4	39.2	2764
5	39.4	2774
6	39.6	2795
7	39.8	2782
8	40	2784
9	40.2	2798
10	40.4	2824
11	40.6	2849
12	40.8	2842
13	41	2858
14	41.2	2861
15	41.4	2901
16	41.6	2892
17	41.8	2904
18	42	2919
19

View attachment 206207View attachment 206208
View attachment 206209

Thanks for sharing your results, hopefully it will save someone a bit of money in their load development.

Wonder what speeds I can achieve out of a 16" barrel?

 

[Bavarianbrit]

Slightly off topic but like all businesses why can the stalkers not just pass on the higher costs of non toxic for sighting in and culling to the game dealers? It is they that have changed the goalposts after all? They in turn will make the customer pay the extra.

 

[DCG]

Slightly off topic but like all businesses why can the stalkers not just pass on the higher costs of non toxic for sighting in and culling to the game dealers? It is they that have changed the goalposts after all? They in turn will make the customer pay the extra.

Let us know how you get on

 

[Bavarianbrit]

Sadly here in Germany the dealers are not squeezing our nuts ref non toxic projectiles yet. I am looking forward to that.

 

[borbal]

The Quickload data I’d acquired suggested that 42 grains of RS 52 loaded at 2.800” coal (head to tip), ignited by a BR2 primer, predicts peak pressure of 45647psi out of a possible max pressure of 60191psi, which should achieve a velocity of 2805fps out of a 24”barrel and a propellant burn of 99%.

The QL data had a COAL of 2.800", but....

..... So running a seating depth check showed that the bullet was engaging the lands with the bullet seated at COAL 2.697”(head to tip),

and,

The Fox bullets ....need to be seated about 0.150” deeper than the average lead bullets of an equivalent weight (up to the bottom of the last cannelure)

Which means there is significantly less room in your case than QL was using to generate that data.

That being the case, the conclusion that,

.....RS52 yet again shows to be more lively than Quickload predicts,

is not really justified.....

 

[DCG]

The QL data had a COAL of 2.800", but....

and,

Which means there is significantly less room in your case than QL was using to generate that data.

That being the case, the conclusion that,

is not really justified.....

Yes I’m sure that the situation is exacerbated because of the restricted case volume when seating the Fox bullet deeper, but why do I find a similar situation when using a 139 grain Nosler Ballistic Tip or SST, seated to 2.800 coal, when using RS52?

 

[DCG]

The QL data had a COAL of 2.800", but....

and,

Which means there is significantly less room in your case than QL was using to generate that data.

That being the case, the conclusion that,

is not really justified.....

Ok, so I don’t have Quickload, but when the opportunity arises I’ll ask someone to input the data with the correct barrel length and seating depth so that I can make a direct comparison.
Instead I‘ve used the online program P-max, which I believe is your creation, and I’m getting very similar results to Quickload, which shows velocity’s achieved approx 250fps faster than predicted, or am I getting something wrong here.

 

[borbal]

Instead I‘ve used the online program P-max, which I believe is your creation, and I’m getting very similar results to Quickload, which shows velocity’s achieved approx 250fps faster than predicted, or am I getting something wrong here.

You stated in an earlier post that you do not know your usable case capacity. I have made a little video showing you how to do this accurately, but you have given enough information to make an informed guess. From the Nosler reloading data, we can estimate that for a 130 grain conventional jacketed lead bullet, the usable case capacity (the volume left in the case for the powder charge once the bullet is seated) will be about 49 grains H2O with a 2.8" COAL.

But this is a less dense brass/copper solid projectile, so will be longer for the same weight, and so will sit deeper in the case for the same COAL as a conventional lead jacketed bullet. You also state that the Fox bullet is up against the lands at 2.7" COAL, and that "The Fox bullets ....need to be seated about 0.150” deeper than the average lead bullets of an equivalent weight"

So, in consequence of this, let us reduce the usable case capacity to 46 grains H2O. Here is what I get with the BBT P-Max app.



Note that I am using the "monolithic solid" as a bullet type option. The resulting MV is now just 36 ft/sec less than your measured 2919 ft/sec, which amounts to a pretty fair agreement.

 

[DCG]

You are entirely correct that the useable capacity will be a lot less than a “normally seated” bullet
However I wasn’t sure about the monolithic solid selection, as their literature states that the Fox bullet has been specifically designed with multiple canalures (driving bands) specifically to reduce pressure, more akin to the bore rider with drive bands selection.
Selecting this option gives a muzzle velocity of 2710ft/s.
We’re obviously arguing over split hairs here. I’ll do some further testing and compare them to both PMax and Quickload, as well as seating some standard bullets deeper and measuring the useable case capacity for each of the seatings, before coming back.

 

[borbal]

We’re obviously arguing over split hairs here.

Indeed.

2710 ft/sec is still (almost) within the 100 ft/sec accuracy cited for P-Max, so I think the powder model for RS52 is reasonably good, and is in general agreement with the Chemie Swiss load data.

Experience has found that despite the friction reducing grooves in the Fox bullets, a better match to measured velocities is achieved if the 'monolithic solid' bullet type option is used.

 

[DCG]

Ok, just back from a couple of days away at the bucks, I’m pleased to report that the bullets performed excellently.
Four animals in total were dispatched, two older bucks, going back overs, taken at about 180m and 120m and two poor button bucks one very poor small animal and one with foreleg joint and hoof deformity taken at about 90m, the other again at 170m. Three classic high heart/lung shots, the very slight button buck jumped straight up not quite a classic forward reaction, turned ran/ fell fifteen feet down the bank and went down for good. The other two more mature bucks went down were they stood. Where the round entered the chest cavity it had opened up to about three times the bullet diameter and on leaving it took out a rib leaving approx an inch and a half hole. Top of the hart, lungs, etc destroyed, ejecting some of this tissue as well as leaving an excellent blood trial. No sign of any fragmentation penetrating the diaphragm and entering the abdomen, very much like a traditional soft point.
It’ll be really interesting to see how they perform on larger animals, but so far excellent results.