Just Fyi For Kirby And 270 Am Owners...

[Derek M.]

I thought I'd post some results I've had while doing a few 270 AM testing.

150 Nosler Btip. (oh, I guess I should start with the rifle....LH stainless 700 action, #5 Lilja, 28" long, fluted, built by APS, H-S Precision stock).

I did pressure tests awhile back to find out max load for my rifle. Turns out it will easily digest 107.0 of WC872 with the 150 Btip seated at the lands. Any more than that is too much. 104.5 and 105.0 produced sub-moa groups...roughly 1/2 moa, twice each. On the first day, it was in the 60s and about 45% humidity. The second time it was 80 and 65% humidity. So, I knew I could work with both of these, which I did.

Ultimately, if I seat the bullet .002 into the lands, OR .005 off the lands, I shoot 0.2" groups at 100 yards. This is odd, as it has never happened to me before, but I'll take it. When the bullet is seated deeper, the groups open up to .650" on average, but no more than .750".

Berger was kind enough to send me a free box of 150 VLD bullets to test. Again, 105.0 grains of WC872 was very good with the bullets at the lands. So, I loaded them 0.005 into the lands, and with 105.0 grains, shots one and 2 made ONE hole. I thought, this is it, let's see what #3 does. The bbl cooled for 25 minutes while I played with other rifles. Shot number 3 opened the group up to about the size of a .308 bullet. I was thrilled. Unfortunately, even though the bolt lifted fine, the primers showed cratering, mildly, surrounding the firing pin indentation. No sticky bolt at all, fired cases measured fine.

I'm using Fed 215 Match primers. Whether or not they are just a little soft, I don't know, but I will play with the powder charge by reducing it in .4 increments with the bullet seated exactly the same to see what happens. But as of right now, I cannot complain at all with the 150 btips, and If I can keep the Bergers about where they are now and give the case a mild diet on powder, I'm done with these 2 bullets. Very cool and kudos to Berger. Once I polish this up I will test them to 600 yards if I can go when it is not over 80 degrees.

I also loaded up 95.0-102.0 grains of Hodgdon US869 with the 150 Btip, all seated at the lands. No pressure signs at all, so I may add powder, I may not, and my target results will explain.

When I did pressure and max load testing with the WC872 and this bullet, I got an array of random holes at 100 yards and 200 yards, but all were 1.5 moa or close. Today, I noticed that the entire group from 95.0 grains to 98.0 grains measured into a nice 0.650 cluster. 98.5 to 102.0 did the same thing but 1/2" higher. Much like if you were to tape a couple of dimes to a target, one above the other. I was impressed, but this can pose a bit of a problem, meaning many charges with this powder will work very well, so now I will start with 100 grains by 3s and see how they do. I'll probably finish at 104 grains. If too hot, I'll pull them.

If anyone is wondering, I didn't get to chrony today.

I also tried Vihtavuori N165. Obviously, this powder will only fill the case to roughly 85% capacity and I found that even though there's a lot of air in the case, this powder did extremely well also with about 81.0 grains/150 Btip being near max.

I will have to suggest that the fact is, Kirby just built a helluva shooter. The **** thing just shoots well and that is all there is to it. I am not crazy about how dirty the 872 burns, but I have 16 pounds of it and I've already discussed what happens with the VLDs and Btips.

What will be interesting is when I finish with the 869 powder and both bullets also. And, I'm not done here either. I still need to polish up with the 169.5 bullet and for grins, will see if I can get the 130 E-tip to be just as impressive. I'm wondering if the rifle will accept 105.0 grains of the Hodgdon powder and the 150 grain bullet.

No matter what, this rifle is going to TX the first week of October for my hog/antelope hunt.

My interest in bullets OTHER than the wildcat are due to a couple of reasons. 1) Dan Lilja used his 270 Weatherby with 130 btips and a 30" bbl on game and killed them to and/or beyond 1000 yards--so I figure if they worked for him, a 150 will work for me on antelope. 2) I have a ton of them that didn't shoot well in the 270 Win.

When I finish with the Wildcat bullet, I can post results also, but I'm sure it will mirror yours or be close.

 

[royinidaho]

Derek,

Great post.

However "Unfortunately, even though the bolt lifted fine, the primers showed cratering, mildly, surrounding the firing pin indentation. No sticky bolt at all, fired cases measured fine.

Unfortunatly???????

Its a personal preference thing, I suppose, but your use of "mildly" pretty much defines a not near maximum load.

Regarding US869 and Nosler 150 Ballistic Tips. @ 30 or so degress and 101.8 grains its pretty much tops. I've backed down to 101 gr and 3500 FPS. As you said accuracy is unbelievable.

I sure wish the Bergers had a better BC but then, the WC 169.5s are available.

99 grains of US 869 and the 169 WC for 3300 is max in mine. ES/SDs aren't so great though.

Will be interested in you chrono data.

Don't get tinkeritus and run 100 unnecessary bullets down the tube. Nevertheless she's holding up just fine.

I'm glad you like her.

 

[Derek M.]

Derek,

Regarding US869 and Nosler 150 Ballistic Tips. @ 30 or so degress and 101.8 grains its pretty much tops. I've backed down to 101 gr and 3500 FPS. As you said accuracy is unbelievable.

That is interesting. 101.8 gr is your max at 30 degrees. 102.0 at 80 degrees was still fine in my rifle--no indication of pressure whatsoever. After the range results, I'll just call it a day and leave 102 at my max. Like you said, I don't want to burn up too many bullets but the rifle has had 52 through it by me, so it could be just now considered "seasoned." Who knows.

What primers are you using?

All of my case necks are annealed. Don't know if that makes a difference.

I know what you mean about the BC of the various bullets, but I look at it like this, which is flawed thinking for LRH/LRS, but even a Berger and ballistic tip will get to the vitals at 1000 yards, despite their non-stellar BCs.

 

[Fiftydriver]

If the cratering on the primer is the only pressure sign you see and your primer pockets are holding snug, I would not worry about pressure as its likely caused by the size of the firing pin more then anything else. Why modern rifle makers will not put a 0.062" firing pin in rifles loaded to high pressure is beyond me as this would solve the issue.

Its really a non issue as long as your not piercing primers and there are no other pressure signs. All alone, I generally do not see this as a legitimate pressure indicator.

As far as the lower BC bullets working at long range, certainly they will. That said, if the wind is blowing or you have multipul wind directions you have to deal with, the high BC bullets make it easier to dope the conditions simply because they are less effected by external forces(wind).

I have never said the conventional BC bullets would not work well at long range, I have only said that the high BC bullets make hitting the vitals at long range much easier in less then ideal conditions.

In good shooting conditions, any accurate bullet will get job done for sure.

 

[Derek M.]

Why modern rifle makers will not put a 0.062" firing pin in rifles loaded to high pressure is beyond me as this would solve the issue.

Can I send you my bolt so you can replace the firing pin assembly? You think it's necessary? I can ship it next week if you advise.

As far as the lower BC bullets working at long range, certainly they will. That said, if the wind is blowing or you have multipul wind directions you have to deal with, the high BC bullets make it easier to dope the conditions simply because they are less effected by external forces(wind).

I agree.

I have never said the conventional BC bullets would not work well at long range, I have only said that the high BC bullets make hitting the vitals at long range much easier in less then ideal conditions.

I know. You've always been nothing but helpful, and I do remember you remarking on the 140 AB. I wanted to play with the other bullets simply b/c I have a ton of them.

 

[Fiftydriver]

Its more the diameter of the firing pin hole just as much as the diameter of the firing pin.

Firing pin should be right around 1/16" diameter and the firing pin hole just large enough for the pin to freely pass through.

In your situation, its more of a nusiance more then anything, I would really not worry about it as long as there are no pierced primers.

 

[royinidaho]

Derek,

If I recall correctly my chamber may be a bit different than your's.

I doubt that any two barrels would act exactly the same anyway.

I use Fed 215 GM primers but just learned that Kirby thinks better of the 215s from a recent post.

However, velocity is good accuracy is good.

I thihk if the west nile hadn't gotten so many Magpies I would have had the 500 yd one by now.

 

[Derek M.]

I don't know what primers are best but I'm sure not going to complain about my results! I'm tickled to death.

 

[royinidaho]

As it is at this point, she out shoots me.

I am really amazed at the long range potential accuracy of the combination of AM and WCs........