7saum load development issues

[AKShooter]

Hello

Well my Saum issues continue. Custom action custom barrel. Originally I had pressure issues with very light loads. Or pressure signs on brass, but still low velocity.

First the rifle went back to Smith who determined there was a bit too must head space. The chamber was re cut I was getting pretty bad bolt thrust. New chamber and making sure I used some brake cleaner in chamber fixed things up a bit. Was able to get more "normal" results

Currently working with some 180 bergers and hr831sc. I've determined 56-57 is close to max for the rifle. Started getting a sticky bolt and pressure signs north of that

Went back to range with 56.5 loaded with different seating depths, all off lands. Had a clean chamber. But every 1 out of 5 rounds leave me with a sticky bolt. And ejector marks on brass. Almost to a point that I'm going to clean the chamber AND loaded rounds....

What are other Saum shooters experience with this??? Is this issue common?

I have been fireforming a 6 Dasher and shooting in a 300wm with no issues. Seams this one is a bit of a problem child trying to figure if it's typical for chamber or if it's back to my particular rifle.

Thanks. Open to any tips from fellow 7 shooters

 

[AKShooter]

Also. I have a pretty decent loading regiment. I did just start using stainless pin media to clean. This brass was left over from the corn cob tumbler. But it's not like I'm dropping and handling brass with greasy hands either. Accuracy has been Ho - hum. Barrel is a copper mine still. Even with 200 or so through it.

May have a local Smith run through it too. My first Saum. Never owned a wsm. Shoot 300wm. Dasher 308. 375 ruger. All with good results. Are these short fat mags prone to this? My thoughts are they are too popular for this to be typical? Don't see many posts about similar issues?

Thanks.

 

[trailrider121]

I'm using 180 Hybrids,and tired H4831, H1000 ,and Retumbo in my 24" 7mm saum using. They all shot well; however, H4831SC gave weird pressure problems at 61grs. It would be fine one day, then the next time out I would get light ejector marks. Seems to work well with lighter bullets. H1000 and Retumbo really produce great speed and groups, and I'm currently using Retumbo. I don't have any pressure problems, but its a full case of powder.

There are others that have problems with H4831 and 180's. Bummer to hear your have those kinds of problems and hopefully you get it worked out. Try a different powder like 7828SC or H1000.

 

[dragman]

What are reamer specs???? Throat length, neck, etc. Also who's brass are you running. I love the short fat rounds and my 7saum was shooting lights out. Burnt out barrel sent it to my smith and it came back just as good if not better.

 

[AKShooter]

I'll give some different powders a go. Been trying to get some h1000 but have yet to see it in my area

I'm all over the place with brass. Using nosler, Remington and Norma. Norma has given me good results.

On the reamer. I do not have the specs but it is throated for the 180 berger. To do it again would have opted for something in the 160 range. I got some 150 long range acubonds but if I seat them to lands the bullet does not have enough bearing surface to seat. Bullet is practically out of case.

 

[dragman]

What does your loaded round measure? Prepped brass measure? And fired brass measure for neck diameter

 

[AKShooter]

I'm up on the Arctic ocean right now, we have wireless up here too. I have the info in my books I'll be home this weekend and will post the info.

 

[dragman]

That's cool

 

[BT1]

I just started shooting the 7 rsaum late last year. Due to the lack of powders normally used with it, I tried IMR 7828ssc, which is still available.

It has since proven to be a more consistent load over H3841sc and H4350. That is also true in my 2, 284's which also like to burn the same powder. More velocity with same pressure ratings, ref, QL and my own bench data.

Load data:
custom 7 rasum reamer basically standard with a 35 degree shoulder
Norma 300 saum cases necked down & turned
Powder IMR 7828 ssc, 60.5 gn. No pressure signs. Have tested up to 61.5 with some minor pressure sign
Primer Fed 215M
Bullet Berger 180 hybrids jump .010"
2990 fps, 32" barrel.

Be happy to share other data points if you are interested. This load has a very low velocity spread and has held vertical spread in the 4" range at 1000 yards. I currently shoot F-Class open.

 

[AKShooter]

I'm going to wing it from memory, also, going to try the berger method for finding the proper seating depth, have not gone through that exercise.

The chamber was touted as a tight neck. End the end, it was not. Still had adequate neck clearance with untouched brass. In my eager to get the rifle, I had neck turned the brass I did have. Pretty sure it was turned to .013 I was able to get my hands on both norma 300saum brass and some (just last week) Remington 7saum brass. I will repeat all loadings with the unaltered necks......I've been shooting a batch of necked down and turned nosler 300saum brass.

For overall length, I was at 3.15 OAL (I can't remember the loaded neck length) This had me approximately .015 off the lands.

My main rub, is this thing is just not acting normal, I've run a ton of loads up. And get consistent results. Pressures start to increase, primers all start looking the same.

This thing just has me on my heels, in a loaded group, 3 of the five might be fine, but 1 or 2 will be different, resulting in a sticky bolt. Frustrated for sure, just never had issues like this with a rifle, also a bit pissed shelling out the big coin to get to this too.

I'm going to completely start from scratch in the coming weeks. Totally strip the gun, clean, lube. Then start with new, unturned brass and the berger 180's. And start from there. I have H4831SC and H4350. All I have for right now. Going to clean the chamber with brake clean, and even give the shells a once over.

Largely my post was to ask fellow saum shooters if they we also having any issues, kind of appears no

Thanks for the powder recommendation, I'll keep my eyes open