Just shot a new tikka 7mm-08 and got flattened primers and sticky bolt with the following load.

Virgin lapua brass, full sized and trimmed.
51 grain ramshot big game
CCI magnum primer
120 ballistic tip
Bullets are way off the lands as the throat is pretty long in this rifle.

I don't try to load my other rifles hot so never experienced flattened primers or a sticky bolt lift. This was my first outing with the rifle so the only thing I can think of is that the mag primers or the dyna tek bore coat raised pressures. Does that make any sense? I cleaned gun with wipeout and then shot some Nosler factory load 120 ballistic tips and no issues. I'll start low and work up my next load but was surprised at the pressure signs on the initial loads. I'd like to run these slightly hot as I've read big game will burn dirty at lower pressures.

Better to start from the bottom than the top.

The information (warning) at the bottom of a quickload data result.......applies to all loads found everywhere, and often SEEMS to be ignored in some posts online and it's a big one.

The variations in powders alone make it important to start lower and work up.

My 2 cents.

See one below.

"Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 87 25.00 1695 1754 30806 3379 98.4 1.473 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 87 25.00 1500 1374 21581 3117 85.2 1.725"

God Bless

Three things:

1. Lapua cases typically have a smaller internal capacity than other brands due to their robustness!

2. Magnum primers are not necessary here!!

3. Always start low and work up, not the other way around!!!


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Tikka #1




Tikka #2




Remington brass. No issues.





P

Just checked my records, I started with 50.5 grains, not 51 like I said earlier. I loaded 50.5, 51 and 51.5 but never shot the 51 and 51.5 due to the pressure signs. I guess like others said I should've started lower and I will. Just seems odd that the 50.5 is a middle of the road load in nosler book and lots of others have used similar loads with no issues. Was hoping to get results like Pharmsellers. I think it must be the Lapua brass having less case capacity as the 51.5 load had the powder filled up to the base of the neck. I'm going to start lower and try Fed 210 primers for the next go around.

I use Lapua brass also and 50gr of BG is pretty full, even at 50 gr and I did not get great accuracy. I still have some work with that load but Re-15 works well.

My hunting load is 49.0 gr of Big Game with a 120 BT. That load is very accurate in my 700. I use a GM 210 primer and I am seated 0.020 off the lands.. RP brass.

Why did you FL resize new brass? Die adjusted right? Headspace OK? What was your velocity?

My deer hunting load this year.
7mm-08
120 Nosler bt
51gr big game
fed 215m
lapua brass
No pressure signs, not sure on velocity battery died on chronograph will check next time out.
Load shoots very well in my rifle .5 at 100

I had a .264 WM that I treated with bore cote, and I had obvious pressure signs with less than max "book" loads. Took it to a gunsmith who ran gauges down the bore and he found what he called a constriction a few inches ahead of the throat. I'm not saying that's happening with your rifle, just something to consider.

I haven't tried Big Game with the 120 NBTs, yet. I only use it with the 140s. I use Varget for my NBTs and WLRM primers.

I'm starting to question whether that is my issue. However, I gave the rifle a good cleaning with a tight fitting jag and didn't feel and tight spots (not very scientific I know). I'm going to load up some minimum loads with Fed 210 primers and shoot them today to see if any issues. Appreciate all the information from everyone.

I'm not blaming it on the bore cote either, if anything it may have been operator error with the application process.

Same here, I could've inadvertently had a pool of it in the throat of the barrel. Too many variables to know what caused it but I'm going to range shortly with some new loads so hopefully have some good news later this afternoon.

Got it dialed in with 50 grains and Fed 210 primers. 50.5 did well too but I think I still felt a very slight (could be in my head) sticky bolt so going to leave it alone at 50.

https://www.24hourcampfire.com/ubbt...eries/13253607/tikka-t3x-groups#comments

I started with Varget but got slightly better accuracy and much more velocity with BG.

I emailed Ramshot asking specifically what the MIN and MAX grain loads were for 120 Nosler BT, 139 Hornady BTSP, 140 Berger VLD Hunting, 150 ELD-X and 160 Sierra grain bullets using their Big Game.

They replied quickly, good service!

MAX for the 120's were 50.0 grains/3150fps/97% capacity.

Where did you get the information that 51 grains was within the MIN and MAX recommendation.

I'm shooting Tikka 7MM-08.

Nosler load data says 52 grains.

Someone already asked, but I didn't see an answer. What velocity were you getting?

Jeff

I shoot the 120 gr. BT over 48.5 gr. of Big Game in Lapua brass for a velocity of 3100 fps. When I switched to Lapua brass from Remington, I had to reduce the load from 50.0 gr. which was also 3100 fps load in my rifle. You should chronograph your load as you may still be a little stout in Lapua brass even though you see no pressure “signs”. And I’ve never had a problem with Big Game shooting “dirty” and my loads are all a little shy of maximum.

Yes, in Nosler brass. How does its capacity compare to the Lapua you're using?

Did you fully cure the DBC, or just fire the one shot before cleaning the bore for the first time?

In reference to Mathman’s question above concerning case capacity, I went searching. I can’t seem to lay my hands on all of my records, so I weighed the water capacity of five pieces of Lapua brass and five pieces of Remington brass and averaged each group of five. Average water capacity of each is as follows: Remington brass held 56.1 gr. of water
Lapua brass held 54.3 gr. of water

That is almost two grains difference in 7mm-08 brass of different manufacture. Sorry, but I don’t have any Nosler brass to compare. I think this unscientific experiment shows a couple of things. 1) your problem is probably powder quantity related due to substantially less volume in Lapua brass causing high pressure, and 2). The need to start low when loading with different components (especially brass). And one other thing.........a chronograph is a better indicator of high pressure than flattened primers or stiff bolt lift.

That's what we use in my daughter's 7mm-08 and it is 0.1 grain less than the max shown in the Western Powder load data that I have. ( However I use WLR primers.) It is very accurate. She and her kids have killed mule deer, Coues whitetails, feral hogs, pronghorns and one elk using that load. Can't find the chronograph data, but it runs around 3,050 fps, as I recall.

as some said work up. Lapua brass is heavier ie thicker.. if you want to shoot 51.5 switch to remington or Winchester brass

I did fully cure it, it actually cured for a few months as I didn't have a chance to get out and shoot. I don't think the bore coat had anything to do with it. I treated several rifles with the bore coat at the same time and had no issues. It has to be the lapua brass having less capacity. I checked the water capacity and the lapua was a little under a grain less capacity vs nosler. In this case, as others have mentioned, I should've started lower instead of starting at a mid range load.

My first two 7-08s couldn't handle the Nosler load max. Despite the pressure signs, the loads shot extremely accurately. I reduced to 50 grains of Big Game and pressure went away and accuracy was similar. My third shoots the same leftover loads very well, so I stuck with it.

Hopefully, I've learned to stop selling these rifles!!

Still haven't seen any velocity readings. If you're trying to figure this out, without a chronograph, it's just groping in the dark.

Just checked Quick load for fun, it says 51.5gr of Big Game is about 72,524 PSI. Maybe why bolt is a little sticky.
Quick load says 48.4gr is 58,000psi wit the 120gr BT at 3120fps.
RL17 with 50.4gr and 120gr BT at 58,000 should give about 3198fps and I would start a little lower.
RL16 with 50.1gr and 120gr BT gives 56,981PSI because that all you can get in the case. at 3165fps.
Ramshot Hunter 51.9gr 120gr BT gives 58,000 PSI at 3138fps.

Check Lastrounds load above. a lot safer.