300 rum Sendero

[dcederberg]

My Sendero shoots 168 Bergers under a half inch but I have been trying to get big bullets to shoot without much luck. Have tried 210 Bergers,200 SMK, and 208 Amax so far. All with Retumbo and at different seating depths. Have any of you had this problem?? The best it has shot is around an inch with 208's. I know I need to shoot bigger bullets but getting tired of trying, very frustrating.

Ceder

 

[Wachsmann]

Are you trying to load to mag length. If so then about .75 was the best I ever got with 210 VLDs. I would think, of the bullets you mentioned the amax or the SMK might be easier to tune. I had to get to about .750 off the lans before I starting getting good groups. I now shoot the 230 bergers and they are at the same place and shoot very well .5 moa or better. Only problem its single feed like this. I did at one point load some 178 Amax's mag length and got good results. .5moa at 100 yards.. it sucks being the mag is so short for the 300RUM. I will later go to a wyatt box mag and have the action blue printed and have a custom 28 inch barrel installed.

 

[dcederberg]

I tried twenty thousands off the lands and they were real bad, forty off the lands shot right at an inch. Should I drop another 10 or try to adjust powder now?? Touching the lands with the 208 is 3.871. Thanks for the help.

 

[Lefty7mmstw]

I like to let my bigger cases have a bit of run instead of getting the bullet close to jamb if I can help it. I'm loading my 225hdy's at 150 thou. off the lands (at max. mag. length) with rl33 in my lh bdl and she's solidly in the .5 to .6 moa range. My 7rum is farther back that that by a mile, but that's another story.

 

[C Harrison]

Powder fill and case capacity may be an issue. Depending on the brass you are using, you may not be able to fit enough powder, or putting too much in the case to get the barrel harmonics just right. Sorting your brass then working up a load with each brass weight lot may give you what you are looking for.

Are your groups showing vertical stringing? How far are you shooting to get a measurable group? I like 300 yards the best as to better amplify velocity variations.

How many grains of a powder increase are you loading between groups with the same seating depth?

It can be frustrating for sure, especially when you have to make a drive to the range.

 

[dcederberg]

I am shooting groups at 100 yards off a bench. I have increased by half a grain on my testing between groups. The last group was at 3.841 and 92 grains of Retumbo. The group did not string, mostly round just not as good as I would like. The rifle shoots 168 VLD's at 3400 into dime size groups.

 

[SLEDGE HAMMER]

Dose it have a brake on it ?

 

[dcederberg]

Yes it does.

 

[Wachsmann]

"Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
1. .010 off the lands (jump) 6 rounds
2. .050 off the lands (jump) 6 rounds
3. .090 off the lands (jump) 6 rounds
4. .130 off the lands (jump) 6 rounds"

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards).
....
I done this but only loaded 4 rounds per group. Also I had 2 rounds to foul the barrel from a clean barrel. I then used a bore snake and ran through the barrel twice between each group to try and make some consistence conditions. I stuck to 91 grains of retumbo. I found 91 grains shot very good for consistence testing. This was done all with the same bullet (210VLD). When doing so the 90 off the lands tighthen up to .75 moa. From this point I went to .095, .085, .075, .070. All were loads of 3. Same method 2 shot from a completely clean bore to foul. Then ran the bore snake through twice. I tried to wait about 3 minutes between shots. The .075 tighten up to about .5 moa. At this point I was happy. I then increased to 92 grains of powder and had the same result with a jump in speed. I went to 93 and then to 94 grains both 93 and 94 opend up and 94 starting showing pressure on my brass. I stopped at the 92 grains and 0.75 off the lans....But when thing got scares (supplies bullets, powder, primers) I went to the 230 bergers. I used someone elses data but at my seating deapth. The gun produced .5moa or better at 200 yards. It was very nice to not to have to tune the 230s all over again. But I was thinking I would have to. I did have to do some bench tuning to get the 230s to .075 off the lan but it paid off before I went out to shot. I am currently going to try RL33 at the same seating depth. Hopefully it will give me similar results or better velocity. Hope this helps.

 

[dcederberg]

Thank you that's a lot of good info. I am thinking I should just jump to the 230 Bergers and start over. Something has to work. How much Retumbo are you running shine the 230's??

 

[dcederberg]

Finally!! 250 yards and shot under an inch. 208 Amax 92 grains Retumbo and 3.741 over all length. I can't believe how much a small change in seating depth makes. It has taken a lot of rounds to get here. Thanks all of you guys for your help. Can't wait to sight in and validate, then ring some steel hopefully at long range

Ceder

 

[Wachsmann]

I hate to ask but what was your final distance from the lans? Just curious to see how this compares.

Also you asked about the 230 bergers. The ones I am shooting are the 230 hybrids and I'm using 89.3 or 89.4 grains of powder. I think its 89.4 grains. If you ever decide to try this start about 87.5 grains and work up. I would have to check but I think the berger book is 88 or 88.5 grains for the 230's is what they have listed.
These will run somewhere at about 2950 to 3000 fps with the 89.4 grains. I think this is a little warm on the load. SO BE CAREFULL and work up checking for pressure issues. Also brass life is about 3 resizes on this load before its trash. I had a separation at 6 reloads. I cut one open at 5 and the lower wall was very thin compared to a once full length sized brass. So that's why I'm limiting to about 3 resizes, 4 shots from one case and then its ready for the trash. This is also all full length resizing each time. I really need to find a shoulder bump die and quit full length resize.

 

[dcederberg]

I have been having the same problem with my Brass, 4 shots and I throw them away. I dont trust them after that. I ended up at .130 off of the lands. There was a remarkable difference in group size, it just took awhile to find the sweet spot. I was just about to give up on these bullets but now I am pretty excited to get shooting them. I really appreciate the info you have given me.

Ceder

 

[dcederberg]

This morning got to shoot a little. Zero at 200, put all my info in my G7 range finder and shot at 400, right on the money 3.8 MOA. Then Went to 600 and it said dial 8.8 and 1,5 wind, two shots dead center 3 inches apart I am very pleased with this combo now. 208 Amax, 3050 fps 3.741 coal, 92 grain Retumbo.

Ceder