7mm SAUM any issues?

[RDavies]

I have only fired maybe 350-400 shots through mine but recently discovered one thing different to my usual 284s.
I started using my latest 284 barrel at the same time as my latest SAUM and they have a similar shot count. I have one of those throat checky things for a 284 so I kept an eye on my 284 a few times and it has only moved .007". My SAUM had started to go off the boil so I expected it to have moved the throat as well but I wasn't expecting it to be .025" movement as I measured it. Of course a sample size of one does not mean much and I suspect my 284 has a hard barrel and the SAUM not so much.

So which powder do you use in both barrels?
Geoff

My 284 uses 2209 while my SAUM uses N165, though I did experiment with a few different powders when I first got it, including 2209. The 284 is run at 2820 fps and the SAUM at 2950 fps so both are in the usual pressure ranges. Like I said, I suspect that barrel hardness might be some of the different between the two. You don't hear too many horror stories of barrel life in SAUMs but on average you will have to rechamber and retune slightly more often than with a 284.

[saum2]

...I do know someone who has a very large stash of it [N165] but wont sell any....i have enough batched 2217 for the next 5 years

There is an old saying about a pot and a kettle....

Alan, i bought the powder on this forum so everyone had an opportunity to buy. How much do you need?

[DaveMc]

I think I had better put an alternate viewpoint to balance out the argument properly

I have now had 5 7mmRSAUM barrels, 2 BRUX, 2 Krieger, 1 Truflite and just about to chamber and fit a Bartlein.
After a fair bit of pressure testing, chonograph work with a PVM and magnetospeed backed up by 1000 yard elevation I settled on 2209 as the go to powder in all conditions. AS Rod said, with such a small sample size (3 barrels in testing but only one batch of fed 215M primers and one batch of CCI 250 primers) there may have been other issues stopping me getting the same results from the other combos as I did with the 2209 and BR2. However -The US team also had a lot of shooters running similar experiments and most also settled on 2209 (H4350) for Raton.

A few of these barrels have done 1000-1200 rounds without any real loss of accuracy run on 2209 - They do now need a push forward of the chamber - 1/2 to 2 inches will tidy them all up.. The two barrels I took to the US and shot 20+unlimited sighters (26 shot string was the longest) in very hot conditions and sometimes in fast bursts - especially in the team shoot need moving forward about 1 inch after 6-700 rounds. They have obvious "hollows" in the middle of the grooves for the first half an inch or so where they got too hot and aren't quite shooting as well as before the trip. They still hold the 6 ring easily at 1000 though. Moving them forward should see another good run out of them and with the max of 2960 fps up here will get to that pretty easily.

If you take your time and shoot steadily you should see very decent barrel life with 2209 (AND THE OTHER POWDERS). Shooting rapid fire strings with a magnum will create heat with any powder and will shorten the barrel life considerably - especially in the first few inches - but a rechamber will give them another lease of life. If you want to shoot rapid fire then perhaps a 284 or smaller might be more applicable? Sometimes there is the need to go fast but at what cost. The bigger the case the more the cost.

Maybe Viht 165 is cooler? I also understand some people are getting good results with 2213SC and 2217 so it is worth trialling all these but I will be sticking with 2209 and have seen some true 1000 yard magic there that will be hard to repeat.

[AlanF]

...I do know someone who has a very large stash of it [N165] but wont sell any....i have enough batched 2217 for the next 5 years

There is an old saying about a pot and a kettle....

Alan, i bought the powder on this forum so everyone had an opportunity to buy. How much do you need?

Well I hope the person you're referring to re: the N165 is not me, because I have sold some of it and certainly don't have 5 years supply.

[AlanF]

I can't help thinking that N165 has suddenly become more sought after because its unavailable. Its been my goto powder since late 2008, was ideally suited to the 6.5-284, being slightly slower burning than 2213SC, and one of the coolest burning powders there is, so I reckon it gave me an extra 300 rounds barrel life in that calibre. When I started using a 7 Shehane 2 years later I kept using it, but its actually not ideally suited for the Shehane, and would be even less so for the standard 284, because you'll fill the case when trying to push the 180 Bergers. The slightly faster burn rate of 2213SC is better suited to the Shehane and standard 284, but most shooters here and overseas favour 2209 because of its famously low velocity spreads. Even with the 7 SAUM, I would be very surprised if either 2213SC or 2217 couldn't be tuned to get equally as good a results as N165. Although I would expect slower throat erosion with N165. But if you did the sums, the higher price of N165 would probably mean higher total costs in the long run. So why do I keep using it? Probably for the same reason I still moly all bullets - if it works, why change? And, I like the aroma (of N165, not moly ).

[DaveMc]

N165 aside, One of the things I don't get is the reputation that 2209 has as a "barrel burner" . If anything my experience is the other way around. I know of plenty of 284's and 284 Shehanes that get exceptional barrel life from 2209. In fact my 2 shortest lived barrels were run on 2213SC (but that is also a small sample size and I think much bigger other factors are at play.)

The biggest killer of barrels is rate of fire and string length without doubt. Just ask the poms shooting Bisley compared to Yanks shooting long strings. What is the "average" barrel life of a 7mmWSM or 7mm RSAUM in both conditions. Also look at the barrel life calculator put on accurateshooter.com some time ago and change the rate of fire factor. I think this factor is magnified as you get more overbored cases (6.5*284 and short magnums etc). Barrel steel will also be a significant factor way above the difference in the ADI powders.

I think people get the impression that "HOT" (being faster burning) means it burns out barrels quicker. In reality you need to look at energy input and energy output to look at "waste energy factor" A lot of this waste energy goes into heat (and noise, muzzle gases, recoil etc - but all things equal heat is the major factor here).

a 56 grain 2209 load vs a 60 grain 2213SC Load vs a 65 gn 2217 load. You need to look at the energy output of each powder per grain used at same velocity to make a comparison - There was a table of the potential energy of each powder on 6BR somewhere associated with the above barrel calculator. I have been through this process once before. All in all I think you will find them very similar in barrel life and hard to distuinguish any difference omongst the larger factors such as rate of fire. I certainly attribute the barrels I have bunt out faster to individual events. Normally I am quite steady with my firing rate but occasionally I will pick up the pace and this costs!!!

Also be careful of comparing some barrels that just keep shooting even though several inches of rifling may be gone!!

You need a VERY large sample size to draw any conclusions here. Anyone blaming the powder on burning out 1 barrel quickly should be taken with more than a grain of salt. Look at the bigger field and statistics please - also look for other explanations

With the upcoming world championships, (hopefully better brass supply ) I am hoping we will see a few more short magnums around and shooters training as much in Bisley as possible. It will be an interesting outcome to watch. Electronic targets and 15-20 shot matches will be an expensive exercise....

[AlanF]

Agreed Dave. The main reason I don't use 2209 in the 284 (at least with the 180s) is it seems to have a sharper pressure curve to achieve the same velocity as the slower powders, and this is not desirable with the 284Win case. However the SAUM clearly has a stronger case head.

[williada]

DaveMc is absolutely correct about the rate of fire. Those who have been doing some load development work with me over the past 12 months on a training project, doing their round robin groups, are strictly instructed to take 45 seconds minimum between shots. Why would you shoot fast on a new green barrel until it passes at least 150 rounds defies logic during the work hardening process of the stainless barrel steel. I think those on the program saw the merit of 2209 with their 284's and Shehanes and have collected a few gongs. David.

[BRETT B]

I think 2209 gets its Barrel Burn reputation from people pushing the Velocity envelope with certain cartridges!! 2209 can burn a Barrel QUICK in over bore cartridges if you start squeezing for a bit more velocity ( eg , 284 @ 2900+ or 6.5x47 at 2900+) . In my own testing I have found it doesn"t take much to get into the HOT zone with 2209 if you get a bit careless chasing velocity to get it into the next node. With any barrel I tune on 2209 now I keep to the low end of the pressure node and it has shown to be very gentle on barrels and shoots very well. With the 284 having a weak case head I believe it has a become a GOOD handbrake for guys tuning on 2209 as it keeps them in the lower pressure node and barrel life is very good. Other cases like Palma,6.5x47, SAUM and WSM have a lot stronger case heads and can hide pressure making it easier to TURN up the charge without realising what is happening in the barrel.

[BATattack]

There aren't many free lunches in this sport so it comes back to barrel management.

If you want a caliber that can win a queen / nationals/ world's but is economical enough to shoot every week at the club get a 284. If you want a caliber that gives more performance and amazing accuracy but for a short amount of time then choose a SAUM.

my main f class calibers are 6.5x47 and 7saum and it just takes more planning with how you test and train and manage those barrels to be working their best when you need them. Some shooters shoot every week or a lot of events where I work toward one event and treat everything leading up to it as practice or testing and the SAUM works well in the cycle of shooting I do. For the guy that likes to shoot every weekend and attend a lot of events it's probably not the best choice.

[RDavies]

There aren't many free lunches in this sport so it comes back to barrel management.

If you want a caliber that can win a queen / nationals/ world's but is economical enough to shoot every week at the club get a 284. If you want a caliber that gives more performance and amazing accuracy but for a short amount of time then choose a SAUM.

my main f class calibers are 6.5x47 and 7saum and it just takes more planning with how you test and train and manage those barrels to be working their best when you need them. Some shooters shoot every week or a lot of events where I work toward one event and treat everything leading up to it as practice or testing and the SAUM works well in the cycle of shooting I do. For the guy that likes to shoot every weekend and attend a lot of events it's probably not the best choice.

Exactly what Mike said. A 284 is the perfect all rounder to shoot in long range club matches as well as some prize shoots and Queens (Marty almost won the Worlds with one), but if you want a special barrel just for the big matches, then it would be hard to beat a SAUM. One analogy would be a 284 is the latest V8 HSV, but a SAUM is a Porsche Turbo.

[macguru]

[/quote]
Exactly what Mike said. A 284 is the perfect all rounder to shoot in long range club matches as well as some prize shoots and Queens (Marty almost won the Worlds with one), but if you want a special barrel just for the big matches, then it would be hard to beat a SAUM. One analogy would be a 284 is the latest V8 HSV, but a SAUM is a Porsche Turbo.[/quote]

I think I really like the SAUM now. Its just as accurate as an equivalent 284, and a conservative load is giving you 2900-2950 fps so you are gaining 100fps. The recoil difference is minimal unless you load hot. Using the same projectiles, with the capacity to shoot 195 grainers. So what's the cost ? Well you need a magnum bolt, and I am using about 59g 2213 instead of 50g 2209 . 9g of powder per shot is not a great expense. The brass, 300 norma, costs less than Lapua 6.5-284 per case, IF you can get some. OK?

Maybe I should not tell everyone how good this cartridge is ....

[Gadget]

Andrew
I have kept my mouth shut about this round since 2010 when we first chambered one up.
Gadget

[plumbs7]

Bush Internet , sorry about the double up!

[plumbs7]

What about 280 AI . Standard bolt-face , better supply of cases!! Any thoughts! Hopefully better barrel life too! I've personally never have used one but I'm sure there have been a few that have .