I've been reloading for a 300 wsm for the past few months and have came across a mystery to me. I can load-up the 150 hornady sst over 66 grains of imr4350 and winchester large rifle primers and get great groups, usually around .4 or .5 for 3 at 100 yds. Thought I would try the 150 accubonds the other day and got poor results. I did switch the primers to federal 215 magnum primers b/c I've read that magnum primers are better for loads over 60 grains. The groups were all over the place. I've got some more loaded-up with wlr primers to see if the primer could be the issue.

So, I know all bullets are made differently, but I would think that two different 150 gr bullets should shoot somewhat similar. The accubonds would shoot around 1.5 to 2.0. Could two different brands of 150's really shoot that much different?

Could switching primers tighten-up the accubonds?

I guess I should just stick with the sst's, but I'm a little woried about their performance on deer.

Short answer, yes 2 similar bullets will shoot that differently. Basically, back to the drawing board when you start changing components. I'll bet you'll probably get better groups with the Accubonds once you find the "sweet spot". Usually 4350 calls for magnum primers. Ball powders will generally let you get away with standard primers.Do yourself a favor and buy some MAgpro. My .270 WSM loves the stuff with 140 Accubonds. I'm getting .25 MOA or better !!!

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Do yourself a favor and buy some MAgpro. My .270 WSM loves the stuff with 140 Accubonds. I'm getting .25 MOA or better !!!

I had a case stick with MagPro in the 270 WSM pushing 140 gr BT's. The load was 74 grs and the temperature outside was 85F. The ammo was in the shade but the rifle was heated up from shooting it minutes ago.

I checked the powder charge and it was 74 grs. I am not sure if MagPro is temperature sensitive but I never liked ball anyway.

So that's it. I am going to try 4831 SC now. RL 22 works pretty well however.

http://www.accuratepowder.com/data/PerCaliber2Guide/Rifle/Standarddata(Rifle)/308Cal(7.82mm)/300%20WSM%20Winchester%20Short%20Magnum.pdf

As already mentioned you have confused the issue by changing bullets and primers at the same time.

While primers can certainly make a difference, I would bet it is the Accubond bullet that is causing you the problem.

I think the Accubond is a great design, but I have had a heck of a time getting them to shoot well for me. I tried the 200 grain version in my 300 Wby Mag that shoots the Nosler Partition under an inch and got 1.5-2.0 inch groups.

I tried the 225 grain version in two different .338 Win Mags and two different 340 Wby Mag rifles, all with dismal results. Then I tried them in a 338 RUM and it shot so well I could not believe it. I got a number of groups under a half inch! So, some guns like them and some do not.

I have not given up on them, I am headed to the range this morning to try the 140 Accubond in a new 7-08 Remington. It shoots 140 Ballistic Tips around a half inch, so we will see what happens.

Try the Accubonds with the WLR primer and try to find the right balance of powder, but your gun may not shoot them well.

I got great groups in a 300 WSM using IMR 4831 behind a 180 grain Nosler Partitions. (with Fed 215M primers)

R F

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Could two different brands of 150's really shoot that much different?

Could switching primers tighten-up the accubonds?

I guess I should just stick with the sst's, but I'm a little woried about their performance on deer.

Yes, yes, and valid concern, in my experience. I also had much more trouble getting light bullets to group, probably because my WSM likes the bullets right at the lands, and 150's are too short to do that reliabily. Try 180's...they will punch through with less meat damage and still drop 'em very quickly, plus they will be more effective if a nice fat feral pig wanders within range!

I've used nothing but wlr in my 300 WSM. Oops, um one load that called for a magnum, IIRC for 125 BT's! Shot lousy so no more of those!

The wide powder base allows you to use standard force primers with all powders. Long narrow columns of ultra slow powders like the 300 wim mag and the ultras, need a long flame front from the primer.

I can`t verify it with hard data but, most of what I`ve read claims the best groups are usually found with the mildest primer that effectivly lights the powder charge. The WLR is a hot "STD" primer you might just not need any more for your load.

I have never found a need with 7mag or less sized cases for mag primers with any powder, baal or stick, I`ve used yet. I do find they are needed in 44 mag with H110 though.

Like the other posters state, changing more then one compontent at a time makes it impossible to pin point what changed what.
....YMMV......

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I guess I should just stick with the sst's, but I'm a little woried about their performance on deer.

Let me save you some headache, If you want an Exit hole, stay away from the SSTs. I tried them for the past two seasons in one of my rifles (30-06) and also loaded them for a relative that shot them in a 300 Win Mag. We killed 6 deer w/ them and he claimed to have hit two more w/ them as well. On 2 of the six deer we recovered the bullet did not exit, they disentegrated. All deer were shot broadside through the ribs/lungs w/ the exception of one which was at a very slight quarter. The SST will make a huge wound cavity much larger than a NBT. If you like a great amount of damage w/ no blood trail, these are the bullets for you.

FYI, MV for the 06 was 2950fps and for the 300 Win Mag it was 3200+ fps. I have seen them do far better at 308 win velocity.

Gutting those deer I killed w/ that bullet was a very messy job if you know what I mean.

On the 150 Accubond note, I just tried some in my 300 WSM the other day and w/ 70 Grains of H4831, WLRM Primers, and Win Brass it was a good shooter. I tried them w/ R22 and they were all over the place. R22 is the best I've found w/ 180 NBTs and 165 Speer HCs in that rifle w/ H4831 coming in close behind. I'm having to seat my bullet way off of the land in this rifle because of my short Magazine length but, it still shoots certain bullets sub-MOA.

Good Luck!

Reloader

I have had great results with the 150 and 165 gr SSTs for my .308.

The last three seasons I have used them, and all the deer were on shot kills. None of the horror storys of massive damage. Only one had an exit wound though, the others lodged just on the inside of the opposite rib.

Just my own experience: try the 165 gr Accubond and RL25 in one of your loads. I'm not going to suggest how much RL 25, but I can tell you from my experience that bot of my 300 WSM's like most any bullet better in 165 gr. over the 150, and I think RL22 is great at the 180 gr. load and could be at the 165. If not, try H4350 with the 165gr.; I try to stay away from 150 gr. in most everything including my favorite 30.06.

Thanks for the replies. I know all about changing 2 variables in an experience at the same time, I do a lot of problem solving for a living. The loads that I found all called for the magnum primers, so I tried them. The rifle is a winchester coyote and have no problems seating close to the lands. I know that the 150's are light for a wsm, but the only quarry is deer. Don't really need a 180 for southern deer. I bought the ssts for break-in, etc, but the magnum primers didn't perform in them either. Usually, I can try some variation of loads that I find with decent success. I tried everything from 66 to 69 grains and all groups followed the same pattern.

I'm going to try the wlr primers on my next range visit. If that doesn't work, back to the drawing board. I could try different powders, but the imr4350 is all I have on hand right now that will work for the wsm. I have noticed that even the 150's start cutting into the powder capacity. Not looking for velocity, just consistency and accuracy. May have to step up to the 165's or something similar, I think the tsx come in the 168 range.

I will post results when I get to the range again. The rifle seems to shoot the sst's real well regardless of powder charge with the wlr primers. I don't reload for a lot of calibers, so usually rely on manuals for starting points. I have read that the Reloader powders are somewhat temperature sensitive, so probably stay away from those.

There is a great article in this month's Handloader mag. about internal pressure and how much the primer will contribute to this problem. It shows that the Win. Magnum primer is one of the most pressure building mag. primers. Surprisingly, the Federal 215 is one of the safest. It just makes sense to me that if you can reduce internal pressure, you are better off.

Sometimes -- not often, but sometimes -- changing primers will produce a significant difference in accuracy. I have found that, generally speaking, loads with magnum primers usually tend to be less accurate than ones with regular primers.

Generally, I think that magnum primers are a mistake unless you have loads with non-magnum primers that are showing signs of hangfires or poor ignition.

I recommend that you go to the FAQs section of Accuratereloading and look at the results of Saeed's tests on different primers.

Since your rifle liked the Hornady SST, why not try the Hornady Interbond? Those two bullets are probably going to be closer in dimensions.

On primers, I used to load for a 270WSM. I cut my groups in half when I backed down to std primers with IMR4350.

Justin B ----- Each run of bullets are to some small degree different. Each company has runs or batchs if you will, of differing numbers. Some run 120 boxs some more some less. There is no way different companys could exactly duplicate bullets. Now that difference may only be one thousanth, but still, that makes a ,perhaps. I say perhaps because in some rifles it may, in others not. Serious reloaders buy many pounds of powder of a particular lot, by the same token bullets bought from the same run or lot should be purchased, if the shooter is precisely measuring groups. An example from my reloading for my .300 Winny. A Fed 210M primer gives one hole groups, changing to Fed 215M, which the book calls for, blows the group to one inch, go figure. ----- Bottom line, changing any component changes the equation somewhat. Good luck and good shooting.

JustinB. I use magnum primers if the load calls for charges over 70grs., thats what I've always read. I always use 180s in the 300WSM, used the Nosler BTs and Hornadys Interbond, both shot great with 67grs. RE22 and WLR primers.
The 150 SSTs will kill deer, but you'll probably get alot of bloodshot meat, lets say over a 180SST, which will hold together better due to it's stiffer construction.
I'd never use a 150 in 300 Magnums, kinda defeats the purpose of a magnum, which in my eyes is to hurl a big bullet at a pretty decent velocity, not scream a light bullet and have half the deer bloodshot. If you insist on a light bullet use the Interbond. Just one mans opinion. Jay

Thanks guys, I'll pass along the input to my brother. It's acutally his gun, I just do the reloading. I will suggest stepping up the grains to something heavier.

Justin, it's NOT the primers. I have seen my groups open or tighten a bit by changing primers, but it won't make a bad load great or vise versa. Your brother's rifle just might not like that particular bullet. The bullet weight is only one factor, bearing length, jacket mat'l. the bullets balance point, all make a diff. I have a .338-06 that just hates 225gr bullets, any 225gr bullet. It shoots the 210grNP better than anything else, shoots 250gr Hornady's into one hole w/ H4350 but not RL19. The 250grGS goes into one hole w/ RL19 but not H4350. Very few rifles will shoot all bullet powder combos well, that's why we handload.