Possible problem with Retumbo

[tymurrey]

I need your help here guys,

Me and friend each have the Remington 700 MLR in .338 lapua. The loads I am shooting are

94.0gr Retumbo
Fed 215 primer
Once fired Lapua brass full length sized
Sierra 300gr Matchking
Velocity: 2650 fps roughly

His loads were

93.5 gr Retumbo
Fed 215 primer
Twice fired lapua brass full length sized
Sierra 300gr Matchking
Velocity: 2760 fps roughly (pressure signs)

We share the dies, the bullets were seated to same length, brass trimmed to same length, same neck bushing. We tried a round of his in my rifle and got the same results as his with sticky bolt, same velocity, other pressure signs and then tried a round of mine in his rifle with no pressure signs and same velocity as mine. He then bought a new lot of powder thinking his was bad and started out with 90.0 grains of Retumbo and is getting no pressure signs now and same velocity as me with 94.0 grains. I know there can be variables between rifles but after checking the first batch and getting same results with both rifles and his new lot of powder getting these results it makes me think I have a bad lot of powder. I contacted Hodgdon and they said they would test it but need 20 loaded rounds sent to them. My question is could there be something else to try before sending them off and probably never seeing my brass again and being out the other components.

 

[MitchAlsup]

Re: Possible problem with Retumbo

A) did you use the same press?
B) were the charges weighted on the same scale?
C) did you measure the sholder position on both sets of cases?
D) do you have a verification weight to check the scale's accuracy?

Why don't you take a picture of the lable of both (all thre)jugs, and send Hogdgon a sample from both (all three) jugs in individually marked baggies (100g each). That is, save your brass.

 

[tymurrey]

Re: Possible problem with Retumbo

The press was different and i suppose something could be different there and i never measured the shoulder position. The presses were both rcbs and set to cam over on the body die and the neck was resized with the same bushing, i guess maybe neck tension could have been different due to different lengths resized but i know they had to be close from looking at the cases but i never measured. The scale used was my rcbs chargemaster combo and calibrated everytime i use it and same when my friend uses it to as far as i know.

I asked hodgdon if i could send some of the powder back instead and he said i could not ship the powder and had to send loaded rounds.

 

[ChrisGarrett]

Re: Possible problem with Retumbo

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: murrdogg</div><div class="ubbcode-body">The press was different and i suppose something could be different there and i never measured the shoulder position. The presses were both rcbs and set to cam over on the body die and the neck was resized with the same bushing, i guess maybe neck tension could have been different due to different lengths resized but i know they had to be close from looking at the cases but i never measured. The scale used was my rcbs chargemaster combo and calibrated everytime i use it and same when my friend uses it to as far as i know.

I asked hodgdon if i could send some of the powder back instead and he said i could not ship the powder and had to send loaded rounds. </div></div>

You're using the same dies/bushings, so unless your case necks are so much thinner on your cases, than his, it's probably not a neck tension issue.

I'm more concerned with his load being .5 grs less than yours, but that ammo is showing severe over pressure issues.

I don't reload Retumbo, nor the 300s, but it would be interesting to see what speeds others are getting.

His powder could very well be the defective powder for the published loads.

Go out and find a different container of Retumbo, from the lot you have and load some more up and see what's what.

Chris

 

[BK7saum]

Re: Possible problem with Retumbo

How old is your lot of powder? Have you left it opened for extended periods of time?

Might not be an issue, but one possibility is that you powder has absorbed some moisture over time. Powder is very hygroscopic and absorbs moisture out of the air. You might not be weighing 93.5 grains of powder any more. Might be 91 plus some water weight?

I mentioned the same thing here


Maybe your powder is bloated?

Sorry. It's late, ah early

 

[Headgear]

Re: Possible problem with Retumbo

Have you used an OAL gauge to check each chamber depth? I'm wondering if his is shorter and the bullet is touching the lands and causing higher pressure.

 

[tymurrey]

Re: Possible problem with Retumbo

We never checked chamber depth, we thought that might be an issue and that's why we shot and chrono'd them in each others gun with the same results in each.