Something wrong?

[tayhot]

I was expecting to get 3200 -3300 fps in a 300 rum. My chorny was displaying 3160 with max loads of retumbo and 180 TTSX. Does this sound right or should I expect better velocity?

I should mention that it was out of a Sendero and at 6000ft elevation. Seems slow to me

 

[justgoto]

You really need to supply more information. I can get those kind of velocities with my 26" barreled 30-06 using 110 grain bullets.
For all we know you are using a 240 grain Woodleigh, with a 20" barrel. And "max loads" is subjective.

[edit] I just noticed your bullet weight, Oops!

 

[tayhot]

180 gr Barnes TTSX with 93 gr of Retumbo. COAL at 3.600. That velocity is pretty much on par with Barnes load data, except they used a 24" barrel rather than 26" like the Sendero.

I tried 185 Bergers and got about the same velocity but instead of 1/2" groups they were 5" groups

 

[justgoto]

My Hornady handbook says a 180gr bullet in a 26" barrel with 93.3gr of Retumbo should go 3000fps. There is only one load lighter than that at 2900. The max load listed is 102.5 going 3300fps, and that has the red block "use with caution" warning.

So it looks better than ok to me.

 

[loaders_loft]

last summer I loaded for a friend's 300 RUM (CDL, 26" barrel) using 180 TTSX, 180 ballistic tips and 180 accubonds with retumbo. The TTSX would pressure out at lower velocity than the nosler bullets. This has been typical with other cartridges as well in my experience.

Sorry I don't have my loading records on hand right now.

 

[tayhot]

What do you mean by pressure out?

 

[Dano1]

Interesting,

When I was working up loads for my Friends .300RUM using 180g Barnes TTSX, I was actually using load data from Hodgdon, but for a 180g bullet, not necessarily a TTSX.

It listed the max loads being 100.5g of Retumbo, so I started at 95g and worked up to 100g and decided that 99g was the best and was certainly reasonable on the pressure aspect. Pressure Signs (stiff bolt lift, bras flowing int the extractor, etc...) started at 100g, but were non exhistant at 99g, so I backed it off 1 full grain. I must also add that these loads were worked up at 80 degree F and we did shoot the final loads over a Chrony. The 99g loads go 3400FPS.

As for seating depth, I just made them fit the magazine, I couldn't do much else as seating for accuracy would make the rifle a single shot, it has a generous throat.

These loads are safe in my friends rifle ( a Rem 700 BDL Synthetic, 26"bbl), I'd look at the Hodgdon web site as well as a few other sources and cross referance the data to see what is out there.

It certainly sounds like you're load is really light What is the Max load you're using???? That would certainly help.

 

[tayhot]

Barnes data is 93 grains as max. I did shoot 94 gr and had no problem with presure. However, I did not gain any velocity (not much anyway) over a chrony. I think it was right around 3130 fps.

I talked with Barnes tech today and I asked them about how they came up with max load. I also asked how much higher I could go and of course they didnt reccomend me going over the published data.

Tried the nosler e-tip today over 96 gr of retumbo and got better velocity at 3275 fps.

My goal was to get velocity up around 3350-3400 max as I thought this round could get me there. I'm kind of scratchin my head because like I said earlier, I'm up at 6000 ft in elevation

 

[MontanaRifleman]

last summer I loaded for a friend's 300 RUM (CDL, 26" barrel) using 180 TTSX, 180 ballistic tips and 180 accubonds with retumbo. The TTSX would pressure out at lower velocity than the nosler bullets. This has been typical with other cartridges as well in my experience.

Sorry I don't have my loading records on hand right now.

I found this to be true in my 300 WSM. When working up loads with RL17 and 168 TTSX's and 180 E-Tips, the 180 bullets got about 50 fps better velocity than the 168 bullets which surpised me.

Typically, you should be getting close to 3400 fps with 180 gr bullets out of a 26" barrel 300 RUM. I am getting 3400 with 180 E-Tips.

Mark

 

[dkolive]

1. barnes manual#4 max 180tsx bt 93 retumbo fps 3171
2. horanady #7 max for 180gr 102.5 retumbo 3300 fps
3. speer 14 180gr max 94 retumbo 3099 fps
4. Hodgdon max 100.5 max for 180gr 3300 fps
5. barnes bullets have longer bearing area and reach max pressure with less powder. It is a good idea not to use data for other bullets. as you can see there is a large spread beteen maxs.
6. sometimes overpressures dont show signs like hard bolt lift/flat sooty primers so be safe.

 

[tayhot]

So what loads are you guys using to get 3400 fps?

 

[MontanaRifleman]

1. barnes manual#4 max 180tsx bt 93 retumbo fps 3171
2. horanady #7 max for 180gr 102.5 retumbo 3300 fps
3. speer 14 180gr max 94 retumbo 3099 fps
4. Hodgdon max 100.5 max for 180gr 3300 fps
5. barnes bullets have longer bearing area and reach max pressure with less powder. It is a good idea not to use data for other bullets. as you can see there is a large spread beteen maxs.
6. sometimes overpressures dont show signs like hard bolt lift/flat sooty primers so be safe.

I guess it's how you define overpressure. For me, as long as my gun operates the way it's supposed to and my brass isn't being damaged, I figure my pressure is OK. I use published mins and max's as a guide and as you can see by the list you made, their levels all differ to some degree. They use different test barrels, different brass, different primers, different bullets, etc. Almost all use a 24" barrel which is not an optimum length barrel for the RUMs. I dont know of any rifle in a RUM cal that is produced with a 24" barrel except maybe the 375.

But you are absolutley right... bottom line is be careful.

Mark

 

[MontanaRifleman]

So what loads are you guys using to get 3400 fps?

I am using 97.5 gr of Retumbo with 180 E-Tips to get 3400 fps. This is 3 gr less than Hodgdon's published max for a 180 bullet but 100 fps more velocity (out of a longer barrel).

I also got 3400 fps with H1000 and RL17 pushing 180 E-Tips. They all maxed out around 3400. I went with Retumbo becasue it filled the case more.

 

[dkolive]

1. I agree mtrifleman/
2. my load for 180 nos acc 94.5 reloader25 fed215 oal is max that fits mag/ fps 3300 / at max load of 95 they list 3359/ max for retumbo is 99 at 3343/ they say out of 26"
3. I tryed Retumbo up to max load did not shoot as good as rel25 out of my gun
4. I shot a mule deer at 250 with the 180 this year at 3300fps left front end uneatable drt
5. You should be able to get to 3400 or close to it with safe work up
6. my gun really likes 200 nos ab 95 gr retombo little over 3100
7. I tend to go for the best shooting load/than worry about fps/easy on brass.
9. when I first got my ultra I crono'ed a 180 partition just over 3500fps a little over the 99gr max load as listed by nosler/ could have been my crono sometimes they read high. Good luck