30-378 reloading with Retumbo

[Greg Nolan]

I ran into real high pressure with the recommended 113 gr. Retumbo (on the container) and a 180 gr. AccuBond. I couldn't find Federal 215 primers so I used CCI 250 LRM. Am I out of luck untill I can get Federal primers or am I safe dropping back the load? It seems I read that you can't drop very much below full loads with Retumbo. I could be wrong. All the other loads I find with CCI250 primers are at 300Wby velocities which are 300 fps. slower.
Good Hunting
Elkhunt :grin:

 

[FOTIS]

I was running 114 with close to 3500 fps with retumbo. No "visible" +P signs.

 

[Greg Nolan]

Pop
Do you think using CCI vs Fed primers could be at the bottom of this? I almost had to use a rubber mallet to open the bolt. The case head had flowed into the ejector hole that much. I found a place that offered Feds for sale and ordered 2k but I've been there before and gotten the backorder till ? notice. I just happened to think, I wonder if my scale is off. It 60+ years old. I'm going to check it.
Thanks for the info Pop. I havn't tried the 200grn A/Bs yet. I was thinking antelope and deer with the WBY.
Good Hunting
Elkhunt :grin:

 

[Antelope_Sniper]

It's pretty hard for an old balance scale to go off, unless something got bent. I believe my old balance before I believe my new digital. My question is did you load the wrong powder??? :shock:
If you have a few more of those loads, pull a bullets. Check the charge weight (were you off my maybe 10 grains, I've seen that happen more then once), check the powder, make sure it really is Retumbo. I'd say check the bullet, but 200gr is already the heaviest AB made for the .30 cal.

 

[Greg Nolan]

Antelope_Sniper
I checked the scale and you are right it was right on per a 110 gr A/B bullet . The powder was right and I verified the weight when I weighed the bullet and went back 2 grs. to 110. It's got to be primer or a real tight chamber or ? I'll check the OAL for bullet clearence to rifling but WBYs are famous for long freebore. :?
Thanks and Good hunting
Elkhunt :grin:

 

[FOTIS]

Honestly Greg, no . Not that much of a difference.

 

[OU812]

Antelope_Sniper
I checked the scale and you are right it was right on per a 110 gr A/B bullet . The powder was right and I verified the weight when I weighed the bullet and went back 2 grs. to 110. It's got to be primer or a real tight chamber or ? I'll check the OAL for bullet clearence to rifling but WBYs are famous for long freebore. :?
Thanks and Good hunting
Elkhunt :grin:

Were these loads with a new lot number of brass than was used before? I've had issues with Norma brass being too heavy which reduces the internal case capacity. Did you work up to the 113.00 load or just went straight to 113.00?

 

[Greg Nolan]

OU812

I started out with brand new Norma brass at 112 grains and didn't experience pressure signs but ran out of brass due to a scope mount problem . I went to brand new WBY brass and 113 grains and had an immediate problem. I should have worked my way up but I normally feel safe with a load printed on the powder cannister as being lawyer-safe. I learned different yesterday!!
Good hunting
Elkhunt :grin:

 

[OU812]

OU812

I started out with brand new Norma brass at 112 grains and didn't experience pressure signs but ran out of brass due to a scope mount problem . I went to brand new WBY brass and 113 grains and had an immediate problem. I should have worked my way up but I normally feel safe with a load printed on the powder cannister as being lawyer-safe. I learned different yesterday!!
Good hunting
Elkhunt :grin:

Did you use the same primers in both loads? I've had the same problem you discribed and it was the brass it's self. One lot number was in spec and the other was not.

I had a load that shot well with no signs of over pressure what so ever, went to some new brass with a different lot number and was way over pressure. Found out the brass was out of spec, very heavy as per Normas weight spec. Ya might weigh some of the brass from the 2 different lot numbers and see how they compare. Norma does have a spec for their brass and you can get it. I have the spec for 338-378 brass, don't know it it would be the same for the 30-378 or not.

As I'm sure you are already aware when ever you got to the same product type but a different lot number you really need to start over. I also found out the hard way.

 

[Greg Nolan]

OU812

Thanks for all of the good info. I'm going to weigh the cases of both lots, Norma and Weatherby(where I ran into the pressure problem). I checked my load book and I had actually been running 112 grs. of Retumbo in the Norma brass and since I had no pressure signs I upped to 113 in the WBY brass. There is definitely a difference. If it's just a matter of reducing load and achieving close to the same velocity that won't matter. I had planned on working on accuracy once I got in the velocity range I was after and that usually means reducing the load, among other things.
Good Hunting
Elkhunt :grin:

 

[OU812]

Your very welcome and I'm glad I was able to offer some ideas. Sounds like your on the right track to figureing out why you had the high pressure spike. Besides weighing the cases the best method to determine internal case dementions is a water test, more of a pain to do but is more accurate.

Do let us know what you find out. 112 in the WBY brass might be too much as well. One would think that since Norma makes WBY brass the internal case dementions would be the same, but they don't seem to be.

 

[Antelope_Sniper]

Brass can be a huge issue regarding overall pressure. On a .270 size case I have to very my loads by 2 grain to maintain even pressure depending on the brass I use. So that mean you might have to vary as much as 4-5 grains to maintain even pressure on that monster of a case you are using. In addition just because brass is made in the same factory, doesn't mean it's made to the same spec. Personally, I think nosler brass is made by Remington, but Nosler will tell you their brass is thicker then Remington brass.

 

[Greg Nolan]

Thanks Antelope_Sniper

I'm working my way up slowly this time. Right now I'm waiting for a Wilson case holder so I can trim the cases. I should be out this weekend or early next week with results. I've been at this reloading a while but I find I keep on learning new things. Thanks for everyone's help

Good Hunting
Elkhunt :grin:

 

[Greg Nolan]

I just got back from the range and 111 grs Retumbo and CCI 250 primers worked perfectly in the Norma brass at 3460fps. That problem is solved but I need to work up a load for the Weatherby brass. Thanks for everybody's help.
Good Hunting
Elkhunt :grin:

 

[OU812]

I just got back from the range and 111 grs Retumbo and CCI 250 primers worked perfectly in the Norma brass at 3460fps. That problem is solved but I need to work up a load for the Weatherby brass. Thanks for everybody's help.
Good Hunting
Elkhunt :grin:

Glad to hear ya got it figured out. Maybe the WBY brass will also work at 111 grains, sure would make things easier to keep track of as to not get high pressure again.

 

[Greg Nolan]

OU812
Thanks
Yes it would make life easier. I'll develop a load Thursday for the WBY brass. I still havn't tried for accuracy yet. I'm just happy it's shooting. :grin:

Greg

 

[OU812]

I thing that comes to mind about retumbo is that it can get HOT real quick, used it in my 338-378. Most WBY's seem to run best at near max but if you can get the accuracy with a few less grains you'll be better off in the long run IMO, nice to have some wiggle room for external circumstances beyond our control.

 

[jtoews80]

Just tried a few loads with retumbo & a 28" bbl WBY Accumark in 30-378.
110.0 grns w/180 grn AB 3425, w/111.0 3465-3475, w/112.0 3560-3610 The bolt started to get a little stiff @ 112, I'll drop down to 111 and stay there, veloctiy seemed a touch more stable. I went up to 200grn AB's w/104.0 grns 3250, w/105.0 grns 3265 and only 10 fps variation.

I fired 15 rounds total during tests, start clean barrel. the first groups were 2 rounds touching and a flyer. This rifle has had a flyer every group on the third shot as long as I've had it if I don't use 2 shot strings. Just too much heat on the barrel. the 200 grain bullets were 3/4" group with flyer due to fouling after testing. Not much of a surprise that the barrel would get dirty burning 1500 grains of powder, regardless of how many rounds fired. I used 3 shot strings because I only had 1.5 hours to test and go back on shift tomorrow.

Worked up a load for 264 win mag with 130 grn AB bullets, 68 grns @ 3245-3250 & 69 grns @ 3330fps, not much velocity spread(20fps). no pressure signs, but tested on clean barrel. Albeit, less than 20 rounds by the end of tests so there was no fouling. I clean the 264 almost every 20-40 rounds because it seems to get dirty very quickly with nosler bullets and particularly with retumbo because of the charge size.
I'll put up with that for the accuracy & terminal perfomance.

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