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300 RUM+180g btip+Retumbo

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Unread 02-15-2006, 07:16 AM
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Join Date: Jul 2002
Posts: 2,855
Re: 300 RUM+180g btip+Retumbo

Out of a factory gun 26 inchish barrel, your pressure is probably very high , I would back off a bit and more than likly that will srink groups faster than adding powder.

As for the FMJ's and coyotes , I personaly think your going in the wrong direction. If your only gonna be shooting out to 300yds then I'd shoot some 35-40gr bullet out around 4000fps (Easy with yout and blow the bullet up in the dog. A few guys I know that shoot for pelts use the 17 cals for this very reason tiny little entrace and no exit.
I know that I can run 40 gr bullets out of a 22" barreled 22-250 at over 4000fps easly so this should not be a problem for you gun and I have never had a bullet exit on anything bigger than a big house cat.
Si Vis Pacem Parabellum
Molon Labe
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Unread 02-15-2006, 10:38 AM
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Join Date: Jan 2005
Posts: 262
Re: 300 RUM+180g btip+Retumbo

I don't want to lecture or try to sound like I'm a reloading "god" but there just isn't a "free ride" for velocity. I just started reloading for friend and I've taken notice of how well that case is made....really thick everywhere. I'm not sure if primer pockets would show expansion like other cases or not. I could post the link to accurate reloading but I'm afraid others might try to use the data. The guys there are VERY EXPERIENCED and got their stock remington to do amazing speeds....I emailed them and said "guy's this just isn't right" and they said yeh but we didn't see any pressure signs.
I'm just not sure we can rely on the usual signs experiementing with this cartridge. (I've also been told that there is no freebore in most these guns which is another factor to consider when you see big velocity)
GOSH VELOCITY HAS TO COME FROM PRESSURE. I sure would like to see some pressure testing done on this big boy to help
drive home the possible seriousness of making this cartridge "sing".
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Unread 02-15-2006, 10:58 AM
Join Date: Nov 2004
Location: El Reno, OK
Posts: 1,497
Re: 300 RUM+180g btip+Retumbo

I have been told to watch the primer pockets on ultra mag brass, I have heard that is where your case will go bad first.

On my Allen Mag I am on my 5th firing and primer pockets are still doing okay, this is with a 104gr load of WC872 with the big ol' 169.5 on top of it.

good luck
Steve Elmenhorst
Third Generation Shooting Supply
"Products for shooters, by shooters"
monday-friday 8:30-5:30 CST
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Unread 02-15-2006, 11:57 AM
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Join Date: Jun 2003
Location: Hermiston, Oregon
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Re: 300 RUM+180g btip+Retumbo

I am aware of accuratereloading. I browsed there and got quite a few loads as a starting point for quite a few of my 300 RUM loads. Especially with the 200g and 220g SMK's. And yes, they are getting some smoking velocities with it, and even there 338 RUM they tested. My primer pockets are starting to get loose, but there are R-P cases and they have been fired 6 times. I dont think I'm all to out of wack here. Just look on the can of REtumbo, it plainly says that 100.5g is MAX for a 180g bullet out of a 300 RUM. So I started at 99g and went to 100g. I was just letting ya'll kow the velocities that went over my screen. THey were very consistent. The extremem spread were only 15fps for the 99g load, and 18fps for the 100g load. IT's only gonna take me 1 coyote to find out if those 55g fmj's will work as well. IF the yote runs off, i'll try my best to plug him again thats for sure. i dont like them running off after being hit with any bullet. I will try for shoulder shots as I like shoulder shots on coyote-elk. If he still runs off, then I will go back to my 2 inch exit holes that the 55g btip at 3925fps leaves. Not much of a pelt saving load there. I dont like these 40g that much cuz there to damn fast, 4500fps. And after about 300 yards, if you dont get a solid hit on them, I fear they will run off. Just not enough bullet and energy left to dump them tough dogs. Thanks for everyones comments. I'll try 101g today adn definately cronograph them. I"ll keep everyone posted.
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Unread 02-15-2006, 05:22 PM
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Location: The rifle range, or archery range or behind the computer in Alaska
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Re: 300 RUM+180g btip+Retumbo

Just look on the can of REtumbo, it plainly says that 100.5g is MAX for a 180g bullet out of a 300 RUM. So I started at 99g and went to 100g.

[/ QUOTE ]

Yes that is what the can sais. I started with a 178 AMAX and 95 of retumbo and locked my bolt in place. Velocity was 3450 FPS. This was not an unussualy hot lot of powder either. This was custom rifle with a tight chamber that doesnt allow for the brass to expand more than .001-.002 of an inch. When you take this expansion out it spikes the pressure. <font color="red"> 90.0 IS MAXIMUM </font> for my rifle at 3300 FPS in 180 ACCUBOND and 178 AMAX.

I am not telling you what to do just please understand that just because the can states you can load 100.5 grains behind a 180 grain bullet doesnt meen it will work for your rifle. Just please be carefull.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
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Unread 02-15-2006, 06:41 PM
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Join Date: Jan 2005
Posts: 262
Re: 300 RUM+180g btip+Retumbo

The can also says START 6% LOWER. But all that aside I'm gonna try and copy over the data they show at Hogdons' website for 180 grainers. Goodness the start load is running 58,000psi and the max is only 4,000 higher for all that difference in powder. I've never seen that many grains make so little difference. I'm beginning to wish I hadn't volunteered to load my buddies gun....it looks like a project I should be doing and watching closely myself.

180 GR. SPR SPBT(Starting Loads)
DIA. .308" COL: 3.530"
H50BMG 103.0 3005 53,700 PSI
H870 103.0 3130 54,000 PSI
RETUMBO 94.0 3182 58,400 PSI
H1000 91.0 3018 52,300 PSI
H4831 84.0 2997 54,000 PSI
180 GR. SPR SPBT(Maximum Loads)
DIA. .308" COL: 3.530"
H50BMG 108.0C 3159 62,100 PSI
H870 106.0 3206 58,200 PSI
RETUMBO 100.5C 3300 62,400 PSI
H1000 96.0 3218 62,800 PSI
H4831 89.0 3167 62,500 P
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Unread 02-15-2006, 06:52 PM
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Join Date: Jul 2004
Location: SW MO
Posts: 1,343
Re: 300 RUM+180g btip+Retumbo

As some of the others have stated, dimensional differences in each rifle can make a difference on max load, but also not all 180 gr bullets (or any other for that matter) are created equal. The length of bearing surface makes a big difference in pressure. I stupidly loaded up 1 gr under what was listed as max with Retumbo for a 225gr bullet behind the 230 gr 338 failsafe in my 338RUM. Sticky bolt and ejector mark on case head! Dropped 3 grains, bolt opens smooth but still ejector mark on case head. When I thought about it, the Failsafe is a flat base bullet with a long bearing surface.

The other guys are right. There is no such thing as a free lunch. The only way to generate more velocity at a given pressure (besides barrel length) is to have a load that reaches the top of the pressure curve faster and remains there longer--more area under the curve.

I know we all want to maximize velocity in our rounds, but gosh, these rounds are impressive enough without pushing the pressure limits. 3300 fps with a 180 gr 30 cal bullet is pretty awesome. Kirby's rounds really push the performance limits, but they have a huge powder capacity to reach those velocities with safe pressure.

I think a person needs to decide what velocity they want with a particular bullet, then look at which cartridge will safely achieve it. I certainly don't want to have to go to the hospital to have primer fragments dug out of my eyeball.(we all should wear our safety glasses--I know I don't always). Just some food for thought.
The critters have to win every time, I only have to win once.

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