302 Whisper

[m21black]

Does anyone have any data on the 302 Whisper?

[Rikky Lee]

I'm currently working with the Lapua 200 grain Subsonic projectile and 110. Results at 50m are one hole but at 100m I'm getting vertical stringing.

Thinking about trying Trail Boss.

[Hoser]

I have been asking that very same question for a while here and elsewhere.

[m21black]

JD Jones emailed me a bunch of data on the 302 Whisper along with the 338 and 375 Whispers last year I just can't find it now... This isn't for me but for another guy, if it was for me I'd call JD up.

[Rikky Lee]

I think we would be all very grateful for any advice on what works. The Laws of Physics are not yet trademarked :grin: so there must be a simple answer to this.

The Lapua subsonic projectiles hit hard and kill fast - much better than SMKs but if the 220 SMK is the more efficient long rang (ie 100 on) bullet then I will try it. Seems to me that Trail Boss offers the answer to the space issue but would also be good to hear some real world experiences with it.

I feel the gunshop is going to be hit hard when it opens!!!

[Hoser]

This isn't for me but for another guy,

That guy from the Hide?



if it was for me I'd call JD up

I did. No info was avail unless I purchased a complete rifle in 302 directly from him.

[m21black]

220 SMK is the more efficient long rang (ie 100 on)

Forget about the 220 grain SMK's you need to understand that in the subsonic world once you hit 1050+/- fps the only way to get more energy is through mass. I shoot the 300 Whisper with nothing but 240grain SMK's they by far have the best ballistic coeffient and are deadly on deer sized game down to squirels. If I could find some 250 grain SMK's I'd have to try them but they are out of production.

[m21black]

how many grains and what kind of velocities?

I'm currently working with the Lapua 200 grain Subsonic projectile and 110. Results at 50m are one hole but at 100m I'm getting vertical stringing.

Thinking about trying Trail Boss.

[Rikky Lee]

With 10.5 grains of powder I get 1000fps ... but ... I need to sit down with a range of loads and chrony and do a proper load table up.

I have some 250 SMKs (precious) so I do not want to waste them. What I want is an accurate 100 plus load with a bolt gun which must be possible. Trail Boss here I come?

Does anyone know what JD's choice of projectile is?

[Rikky Lee]

Here is the results of the velocity testing with the 200 grain Lapua and I think you will see immediately why things have been happening the way they have:

Starting with 11.0 grains of 4198:

a. 847fps
b. 943fps

Av: 895fps but this seems a little on the high side.

11.5 grains:

a. 932fps
b. 1088fps
c. 1161fps
d. 955fps

Av: 940fps (remove b &c due to velocity spike)

12.0 grains:

a. 960fps
b. 981fps
c. 996fps
d. 964fps

Av: 976fps (see that the velocities are stabilizing and there are no spikes)

So what does that tell us? Well it tells me that more powder is needed and a simple straight line graph suggests that 13.75 grains of 4198 should give 1050fps.

Fingers crossed!

[m21black]

post your results with 4198.... please:smile:

[m21black]

Ricky,
Thanks for posting the data...

250 SMK's I'm jealous... a have a couple thousand 240 grainers but no 250's...

[Rikky Lee]

Now things are getting wacky with the 200 grain Laps and 4198...

More loads and a pattern developing:

Grains Av Vel (fps)
11 895
11.5 944
12 975
12.5 1064
13 Didn't try
13.5 1120

Tried 14 grains behind a 220 RN - weird velocity spikes.

BUT!

With the 250 SMKs (How much I hate using them at all!!!) and crying tears between each shot.

16 grains - 4198

a. 1080
b. 1077
c. 1108

Av: 1088fps and SD of 17fps

Now we are getting somewhere - the 250 fills the volume of the case well and the 16 grains sits deep enough for some consistent ignition.

Next steps:

a. Try 15.5 and 15.8 grains of 4198.
b. Get some 240SMKs!
c. Ignore the 200 grain Lapuas...

Wish me luck.

[Rikky Lee]

Just ordered some 240 grain SMKs to try. I'm thinking 15.5 grains should give me the starting point for the load.

Now what is the better muzzle velocity to head for? 1040 or 1050fps as average?

[m21black]

I can recommend the 240 smk's in the 300 whisper... glad i bought a couple boxes a while back on the cheap as they are getting pricey.... paid 100.00/500 shipped

[Rikky Lee]

Received some 240s to try this weekend. They are about the same length as the 250s (1.65 for the 250 vs 1.58 for the 240) so I am quietly confident. Bearing surface seems to be the same ratio.

What these seem to be doing, and what is different from the 200 grain Lapuas, is restricting the volume of the BR case to a capacity where the 15 - 16 grains of powder can ignite consistently.

Results hopefully on the weekend.

[Rikky Lee]

Using 240SMKs ==> 15.5 grains of 4198 = 1020 fps average (good) but Standard Deviation of 48fps (bad).

Trying 16 grains of 4198 and 17 grains 3031.

Then trying for accuracy at 100.

[Rikky Lee]

Latest results with 240 SMK

Using 16 grains of 4198:

a. 1054
b. 1122
c. 1055

Av. 1077 SD: 38. Take out the b shot and you've got some good results noting the small statistical model.

Using 17 grains of 3031:

a. 987
b. 1083
c. 1160
d. 1114

Average of 1086 but SD of 73.

Now to accuracy testing at 100.

Notwithstanding the high SD; the 17 grain load group 3 in a 2 inch group at 100 and one flier (first shot?).

The 16 grain 4198 load shot a 2.5 inch group.

So comparing this result to the 200 grain Lapua at the start of the thread. We have:

a. improved accuracy

b. improved velocity

c. improved on shot to shot variation

Where to from here....

While generally happy with the load I think I shall try 15.9 grains for a ten shot group and concentrate on forming a consistent group with that load.

[Hoser]

Great info.

Let me know how accuracy testing goes.

[Rikky Lee]

OK, this is where things have gone from the frustrating to the obsessive and back again.

Range testing the 15.9 grain load revealed a good group for three of the five shots of about an inch - two touching one out. The other two were six inches vertically low. So this is the same grouping as from the start and indicates the extreme velocity spread (ES) is much too wide.

So what? This is where it gets technical and goes straight to the heart of why Whispers/subsonic loads are so frustrating. Let's see if I can get the description right. The pressure curve in the case is not uniform because the powder is not burning at the same rate from shot to shot. Because the powder is not burning at the same rate from shot to shot, the gas pressure is different from shot to shot and the velocity ranges high and low - which is what you'll see in the velocity spikes in the records detailed above.

It is blindingly obvious in hindsight but the sort of thing you need external advice on. It was also the conclusion that I was coming to after having standardized the load, the seating depth, the velocity etc etc.

The answer is that if you are seeing perfectly vertical groups go to a faster burning powder. With the BR case size you need to look at something in the burn range of IMR4227, H4227 or AA1680 ie a powder that suits both rifle and pistol, very fast so that it can used in a 22 Hornet and also a magnum pistol case.

Back tot the drawing board/reloading bench. My ideal load will have the following characteristics when using a 240 grain SMK.

Velocity: 1045fps
SD: 11 fps
Group at 100: about an inch and hopefully less.

[Rikky Lee]

Results with the faster pistol powder are showing promise. With no load data for H4227 I decided to load three loads; 13, 14, 15 grains to get a velocity trend pattern.

Starting with 13 grains produced an av velocity of 1145. 14 grains produced 87 fps more at 1232 fps. 15 grains was not tested.

The five shot group using 13 grains produced a 2 inch group which showed good promise.

Next loads will be 11.8, 12, and 12.2 grains I think.

Getting closer!

[HotGuns]

If you think that your powder is not burning at the same rate, try backing off the powder a bit and using a magnum primer.

I have done this over the years with various loads and it seems to work.

In your case, it may work or it may not. It certainley couldn't hurt to try it.

[Rikky Lee]

Latest test results:

11.8: 906 fps

12: 918 fps

12.2: 1024 fps

I'm thinking its time to try 10 of 12.5 grains and play from there.

It is also quite obvious from the group's shape that the smaller amounts of powder have the most vertical structure and there is a tipping point in the load where things start tightening up.

[Rikky Lee]

Failure, big and total and unmitigated failure at 12.5 grains. Worst results for while.

12.8? I have had about enough of this though - can see exactly why the 30Br hasn't been taken and run with at the subsonic level.

I will do a bit more experimenting and then rechamber to a 300 Whisper proper.

[HUNTER2]

You have probably thought of about everything, but- Have you tried crimping, and- Would the small amount of extra room be enough for trail boss? And - Who made your barrel?

[Rikky Lee]

Thought of Trail Boss but I do not want to buy a canister that size.

Done the crimping.

Barrel is a local one that shoots 1/4 MOA with 155s.

Feel the frustration?

[Hoser]

Have you tried 220s?

[Rikky Lee]

I have tried:

180s various.

200 Lapua.

220s various.

240s and 250s SMKs.

With the 30BR, supersonic loads for all these weights work very well. It is when you try to get to 1050fps that vertical groups emerge....

One more thing to try and that will be another, faster powder but it does show that the 30BR is not the ideal case for this type of subsonic activity. Part of me would like to try a 30 PPC but rhe reality probably is that a 300 Whisper style would work easily without this level of fuss and bother.

[Rikky Lee]

Success - a move to a faster powder - a straight pistol powder from my 9mm has resulted in a three shot group of just under an inch. Two shots through the same hole.

No velocity yet...

The bulk volume of the powder at 11 grains is significantly more than the bulk volume of 12 grains of the previous powder used.:smile:

[Rikky Lee]

OK then. After a break due to sickness and the birth of a child I did some more work to get this thing running properly.

11 grains - pistol powder:

a. 1180

b. 1228

c. 1187

d. 1218

Average: 1203 fps. SD: 23 fps.

Drop to 10.5 grains for velocity and group testing as the next step...

[Rikky Lee]

Yipeeee!! I shot a 3 shot 100 yard group that measured 0.483 inches center to center.

Velocity results posted soon.

[Rikky Lee]

With a velocity of 1140fps.

Happy.(Well happier!)

[Spook]

What powder was that Rikky?

[Rikky Lee]

Out of frustration I went to a pure pistol powder that I use for my 9mm with a burn rate equivalent to IMR SR 4756. Part of me wants to try a slightly faster powder again.

[Rikky Lee]

9.8 grains shoots well and accurately.

Forgot to take chrony so velocity test later.

Confirm a Sub MOA group at 100.

Still to chrony but the promise is showing.

Funnily enough the 10 grain load showed long vertical stringing but 9.8 and 10.4 don't....

[Rikky Lee]

So here we are - almost at the end of a long journey.

9.8 grains groups well and runs at 1046fps average with an SD of 26fps.

That will be the basis for a series of long range (100, 200, 300) tests and some field work.

Is that a light I see???

[HUNTER2]

Must have missed it...What powder are you using now?

[Rikky Lee]

SR4759 which is a faster burner than H110.

Pistol powders, heaviest bullet gives less air volume in the case - my original problem using the Lapua 200 subs.

[Expatriot]

Forget about the 220 grain SMK's you need to understand that in the subsonic world once you hit 1050+/- fps the only way to get more energy is through mass. I shoot the 300 Whisper with nothing but 240grain SMK's they by far have the best ballistic coeffient and are deadly on deer sized game down to squirels. If I could find some 250 grain SMK's I'd have to try them but they are out of production.

Have you ever had a subsonic bullet stop inside an animal?

If not then that bullet did not impart all of its "energy" inside the animal. Going to a heavier bullet is not going to increase the amount of energy imparted to the animal, all it will do is increase the amount of energy the bullet carries with it out the far side of the animal.

I did a bunch of terminal testing with 150gr subsonics and they penetrate to a huge degree. You are not getting any increase in terminal energy by using a bigger bullet.

[m21black]

No never had a 240 grainer not punch through end exit the deer but the 240 grain SMK with 1:8 twist are not as stable as the 150 grainer bullets that you are shooting. The 240 grainers tend to yawl over on contact thus they dump more enery and make nastier wounds...

[Rikky Lee]

I really like what the 240 SMK can do (and would like to thank m21black for his advice waaaaay back on page 1). Since this thread started I have cut but barrel back to minimum legal and had some good short range shooting.

I have stopped for a while to have a 458 SOCOM installed on this action.

Has anybody made any progress with load development?

[Alpha-8]

[QUOTE=Expatriot;18163]Have you ever had a subsonic bullet stop inside an animal?

If not then that bullet did not impart all of its "energy" inside the animal. Going to a heavier bullet is not going to increase the amount of energy imparted to the animal, all it will do is increase the amount of energy the bullet carries with it out the far side of the animal.


Have you actually ever shot an animal with the .300 whisper?

[m21black]

With your logic you should either to stick with paper clips or 12 gauge shotguns. Exit wound make better blood trails.

[Rikky Lee]

Resurrecting an old post to keep the information all on the one thread.

The 9.8 of SR4759 in a 16 inch barrel seems to do the trick. The old barrel was too long at 22 inches and cutting it back appears to have taken the variation out of the velocities for the 240s.

Happier again. Happier too that I am now using the RCBS Chargemaster to produce more consistent loads.