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7mm Rem SAUM loads for F Class

Wild_Bill

Hi there i have been busy for a while and not around.

I have got my new F Class rifle humming along.

the barrel is a 9 twist and 28' long 9 twist.

The chamber i ran into this barrel is the 7mm Rem SAUM throated .200' i have been working up the load and today i shot 67.5gr Retumbo with CCI250 Primers Rem cases and 175gr Sierra MatchKings, I was realy suprised today i shot it at 300 yards getting a good zero then we went back to 900 yards so i dialed up 16moa and hit high on the target the correct come up was 14.5MOA. this blew me away at 1000 yards it was 17.75moa elevation. the load shoots realy flat at 300 yards i used under 1/2' and at 1000 yards it used around 2' elevation. So from a 100 yard zero it equates to just over 20moa it does not realy work out with balistic programs i have to dial in 3150fps and .685BC it can not be that fast but the projectiles are higher when pushed hard than the Sierra published BC'c i will chrono the loads to actualy see how fast they are going. I have found Retumbo to be the best powder it is just slightly compressed and shoots like stink.

Just a side note we chambered a 284 Shehane last week and fireformed the cases when both cases were filled with water one fired in the previous 284 chamber and the case from the same batch the water volume was only .9gr more i can not see where the extra 3gr of capacity is coming from? If the cases are both throated the same that means a Win case in the standard 284 will have more capacity that the Lapua case formed to the SHehane chamber.

I think their should be some more comparisons on the standard 284 to the improved case like chambering a barrel to the standard 284 then open the shoulder the 10 thou as that is all it is then re firew the barrel to get the diferences i think that their are comparisons here comparing a short throat 284 to a troated 284 shehane that is the only way that 3 gr capacity can be found.

Any way have fun Bill
 
Nice to hear the 7 SAUM is shooting good for you. Im planning to chamber one up in the next couple months. So your getting 3150 with the 175's? thats pretty good speed.

Also, what barrel are you shooting?

Jerid
 
Hi Jerid im not sure of the actual velocity as i have not chrono'd it yet that is just the velocity i had to use to make toe drop work out. The barrel in a MAB that we hand lapped. The other barrel i have is a 6 grove 9 twist 30' Lawton it should be faster.

The accuracy is just awsome i have some Norma Cases on the way they should be a bit more consistant but at the moment i have no issues with the Rem Brass. If you are building one use Retumbo for heavy projectiles it gives more velocity than H1000 with the same powder charge with less pressure it is about perfect. Remember i have the chamber throated 200 thou so if you have a long throated chamber you should be able to match the loads if not you will not fit it all in also drop the loads 2gr and start to work the load up in a long throat in a factory length chamber drop 5gr and work up.

I believe in 7mm it is the best case for any long range target situation all the others are not as well ballanced. This includes the WSM's in either 7mm300WSM or 7mmWSM. the other cases like 284 and 280AI cant match it but in 30 cal the 300WSM is slightly better than the 300 Rem SAUM unless a 2.80 mag is used and in that case the Rem case is also the best to work off.

I do hope the Rem SAUM case takes of it was the best but the marketing of Win worked against them.

Only time will tell

Cheers Bill
Australia
 
Bill, the barrel Ive got is a 4 groove 9 twis Brux. It will be later this year befor I get it ready too shoot.

Ive got 300 Rem case and did some sorting on them and was really suprised how consistant the weights were. 150 case were within 1.5gr. havent sorted the other half yet.

With the .200 freebore, whats your seating depth with the 175's?

Also, Im kind of suprised that the .284 Shehane didnt give more capacity. Maybe it isnt fully blown out? I know my .243Ai takes two good firings before its fully blown out..

Keep us posted on that 7mm.

Jerid
 
Hi Jerid
The 284 shehane had fully formed the case measured the same at the shoulder as the reamer so the .9gr is all their is. The case only changes by 10thou at the shoulder their are no other changes to the chamber other than that.

As for the 7mm SAUM i load them to 3.150' to have them 15 thou into the lands.

Hope yours shoots as well as mine.

Cheers Bill
Australia
 
bill

Are you measuring/checking the Shehan cases after firing or after resizing? the resizing dies that Bill sells for the 284 shehane really undersize the brass by quite a bit. I measured my cases, which are Lapua 6.5x284's, and the O2 was 1.7 grs weight....basically from 66 to 67.7 grs....


Jim
 
Bill:

I see all kinds of case H20 numbers coming from the 284 Shehane. I get different numbers myself when I do the H20 thing (2.2 to 3.35). Heck, you can get .9 difference just from another lot of brass. Having said that, in the real world, don't try 57-58 grains of H4831SC in your straight 284 as the outcome will be an unsafe one. I shoot an easy 2950 fps with 57 grains of H4831SC -- in 100 degree plus weather. No pressure problems at all. I can run 3100 with RL-17 (but I don't like 17). The bottom line is that you can fire form brass with the Shehane at about the max load for the straight 284. That is real world and not measured H20 capacity.

The 7mm RSAUM is also a very fine round -- but no Lapua brass -- but the Norma is working very well with this round. For the man with a standard bolt face, the Shehane spanks a straight 284. That was the intention of the round in the first place, i.e., something to beat the 6.5 x 284 and the 300 Win Mag in prone competition, with a standard bolt face and a short action (works better with a prone stock) and it does.

Danny Biggs sure has his 7mm RSAUM working, and I believe it to be a better LR choice than the 7mm based on the WSM cases.

I love the Shehane and just had to take up for the old girl just a little.


Jim Hardy
 
if you are going to try retumbo in this case the max load given from hogden for a 175gr bullet is 66.0.Not that i have never been over max published load.if you don't have alot of neck tension with compressed loads bullets are hard to seat and will grow in lenght.not a good idea.I loaded some 180 bergers with retumbo to try 64.0,64.5,65,65.5,66.0,66.5 in new cases with a long drop tube.after 64.5 or 65 they are pretty compressed.what i will probly do is use a 215 primer and drop 3 or 4grs off max load of 66grs and work up slow.you will probly whind up with a good load that is not so compressed.
 
I tried Retumbo in my 7rsaum with a 180 JLK and it was alright. H1000 was better with the 180 JLK , one of these day's I'll get around to trying some Berger's.
 
Good point 65 fan on the compressed charge pushing the bullet back out. I don't have a lot of squeeze. I have tried up to 66 grains of Retumbo with a 215 primer, .010" back, and had no pressure issues with my 180 Bergers and Norma brass. Seating I can hear a little crunch so I don't want to try squeezing in more than 66. The recoil is smoother than 62 grains of RE-25 but the necks look more sooted so it may be dirtier? My velocity data was corrupted by the @#!!$ operator. One sensor wasn't clicked in so my spacing was 3/4" off. Retumbo was faster than H1000 and RE-25 in my 30" pipe. Keep this one going folks. Thanks.
 
jarhead1086 said:
Good point 65 fan on the compressed charge pushing the bullet back out. I don't have a lot of squeeze. I have tried up to 66 grains of Retumbo with a 215 primer, .010" back, and had no pressure issues with my 180 Bergers and Norma brass. Seating I can hear a little crunch so I don't want to try squeezing in more than 66. The recoil is smoother than 62 grains of RE-25 but the necks look more sooted so it may be dirtier? My velocity data was corrupted by the @#!!$ operator. One sensor wasn't clicked in so my spacing was 3/4" off. Retumbo was faster than H1000 and RE-25 in my 30" pipe. Keep this one going folks. Thanks.
Click to expand...
I shot a pressure test today 95 degree's retumbo 64.0 2870,64.5 2924,65.0 2952,65.5 2973,66.0 3020.all with 180 beregers and 250 primers.this was shot over crony to target at 418yrds 3 shots had no vertical.I will be lattering her up tomarow. ;D ;D
 
Re-25 is my choice at this point in the testing because it shot a teeny group and had just slightly less velocity than the Retumbo plus I haven't tried finding the ceiling on the charge yet. 62 grains still seems fine but very close to max. I can't put in anymore Retumbo. The WSM guys ought to try more Retumbo and see. I am new to RE-25 and am worried about the temp sensitivity. I have had major problems with N560 in my 6.5-284 from winter to summer so now I am paying more attention. A small hit in performance is worth it to me not having to worry about the temp so much. H-1000 should do better in that regard I would guess. I haven't grouped H-1000 yet.
 
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