Tuning Berger 7mm 190

[dminn1]

I would like to hear experiences with tuning this bullet others have had. I have had a good deal of difficulty trying to get this bullet to shoot to my satisfaction in a 7mm mag long range steel shooting gun I put together. To this point I have been through 500 of these bullets across two different barrels, two powders, two primers, and multiple seating and powder combinations. I have found two promising nodes that repeat in multiple ladder tests at 2840 and 2900 fps. I do all my testing at 200 and 600 yards and have a lot of really nice three shot groups at what I think is the tune only to see inconsistency on the next outing and never half moa or better 5 shot strings. Consistently have 3 or 4 tight shots with one or two stragglers.

Not looking for advice on trying to make these shoot in my rifle as I have already moved on to another bullet with more promising results at a somewhat reduced bc. Just would like to hear if anyone has had success tuning this bullet in this or other chamberings before I sell what I have left of these bullets.

Thanks
Darin

 

[F Class John]

I have them shooting in a straight 284 and a 284 Shehane. Both are keeping sub 3" vertical at 1,000. But to your point, they were a lot more work to tune than the 180's or even the 184's. There's also a lot more data on the 180s to work off of already so that plays in too. I worked from 2700fps all the way up to 2940fps and used up nearly 1,000 rounds just testing them out. But I enjoy doing that.

 

[Tahoe Shark]

And what did you find the 190’s to favor?

 

[whatwind?]

I would like to hear experiences with tuning this bullet others have had. I have had a good deal of difficulty trying to get this bullet to shoot to my satisfaction in a 7mm mag long range steel shooting gun I put together. To this point I have been through 500 of these bullets across two different barrels, two powders, two primers, and multiple seating and powder combinations. I have found two promising nodes that repeat in multiple ladder tests at 2840 and 2900 fps. I do all my testing at 200 and 600 yards and have a lot of really nice three shot groups at what I think is the tune only to see inconsistency on the next outing and never half moa or better 5 shot strings. Consistently have 3 or 4 tight shots with one or two stragglers.

Not looking for advice on trying to make these shoot in my rifle as I have already moved on to another bullet with more promising results at a somewhat reduced bc. Just would like to hear if anyone has had success tuning this bullet in this or other chamberings before I sell what I have left of these bullets.

Thanks
Darin

Can you give all the details of your caliber/cartridge, bbl, powder etc? i need to decide which 7mm bullet next and i am interested to hear all about it

 

[dminn1]

Can you give all the details of your caliber/cartridge, bbl, powder etc? i need to decide which 7mm bullet next and i am interested to hear all about it

7mm Rem Mag, 26" Criterion Remage barrels, 26", 8 twist, custom throated by me to place the pressure ring of the bullet above the neck shoulder junction. I am running this cartridge out of a cip length magazine and coal was around 3.640 with base to ogive around 2.881 at my best performing seating depth of .025 off touch. Powders extensively tested were H-1000 and H-4831SC. Was able to run H-1000 at a node right around 2910 and had to run the H-4831 at a node around 2830. This was about max for both powders. Tested Fed 215M and CCI250 primers with both powders. Best numbers and groups came with the Fed215 with the H-1000 loads and with the CCI250 showing a slight advantage in the H 4831 loads. Ran 250 pieces of Winchester brass for all of my testing. It was neck turned just enough for a full cleanup around the neck which in my chamber yielded about .004 clearance. Flash holes were deburred and primer pockets uniformed with a K&M tool. This brass was weight sorted and had surprisingly little variation for a case this size. Some of these cases have seen 5 firings and the pockets have remained tight at the pressures I have ran them at. I anneal case necks after 4 firings. Neck tension has been anywhere from .001 to .003 with the higher neck tension yielding very slightly better numbers. I full length size the brass every firing and aim for .002 shoulder bump. Feel free to ask if you need any more info.

I failed to get consistent repeatable groups out of this bullet with the combinations I have tried above. We also tried this bullet in a 7SAUM 8.5 twist Bartlein and could not get it to perform as well as the 180 Hybrid.

 

[whatwind?]

Thanks for sharing

 

[Willow]

You probably need to ask members on the US F-Open team for next year's WC. I think they're going to be running the 190s so I'm sure they'll get them humming along.

 

[JJMoody]

If anyone has some they’d part with, I’m looking...
Before I order...

 

[FURMAN]

We just got done tuning a custom throated 7 Rem mag with these and they are holding very tight vertical in a sub 9lbs scoped rifle from prone with a bipod. This is with RL26 and in this rare instance for me with Berger bullets they did not like being within .040 of the lands. We had to back off to .100.

 

[dminn1]

We just got done tuning a custom throated 7 Rem mag with these and they are holding very tight vertical in a sub 9lbs scoped rifle from prone with a bipod. This is with RL26 and in this rare instance for me with Berger bullets they did not like being within .040 of the lands. We had to back off to .100.

Interesting information. I did not try RL 26 or get over .030 off the lands. May be worth revisiting.

 

[dminn1]

If anyone has some they’d part with, I’m looking...
Before I order...

I have three sealed 100 round boxes I would let go. PM me if interested. I would really like to trade them straight across for some 184's.

 

[F Class John]

If anyone has some they’d part with, I’m looking...
Before I order...

Pm sent