300 RUM Barrel Length

[Boss Hoss]

My 300 "Slowpoke" which is an improved 300 RUM likes the H870 much better than the H869. The RL25 works well also but Retumbo at least in my 27 inch Krieger Speedy built rifle is not consistent and is no longer in the mix. Have not tried the Win WMR yet but will when the BR season is over and I get some time I will. FWIW the 190 SMK and the 210 SMK is the favorite pills it likes so far.

The rifle is a 27 in Krieger built on a McMillan sporter stock using a BAT repeater and a printed jewel trigger ----- the Brake is the Speedy design.

 

[River Man]

Boss Hoss,

Thanks for the information.

I am going to get a can of H870 and a can of RL25 to try in my gun.

What grain weight of each powder does your gun like for the 190 and 210 SMKs?

That is probably a good starting point for my gun.

 

[jwp475]

You may have a difficult time finding H-870 since it is no longer made and has not been for quite sometime now.... H-869 took the place of H-870

 

[Boss Hoss]

Sorry but this was in my 300 Slowpoke which is a improved 300 RUM it increased at 5.5% ofer the parent-----my screwup sorry cought it when I reread the post. I would not start with these loads in a RUM by any means.



JWP475 is correct about the H870 but in my gun it works better plus I have 16lbs of it. I only have 1 data sheet with me and I am looking for the other but here ya go --- this was the first rattle out of the box with no pressure signs yet but I an very happy with the 2 200 gr loads.:

H870 106.0 210 SMK = Low 3162 High 3227 avg 3199 10 shot string grp size .6 1 flyer otherwise .45

H869 102.0 210 SMK = Low 2939 High 3003 avg 2975 10 shot string grp size .9 scatered


H1000 94.0 210 SMK = Low 3110 High 3159 avg 3138 10 shot string grp size 1.6 scattered


H870 106.0 200 SMK = Low 3180 High 3212 avg 3193 10 shot string grp size 1.1 vertical stringing may have been my fault 8 shots in .6 several in the same hole best of the bunch and is my hunting load so far


H869 102.0 200 SMK - Low 3265 High 3245 avg 3250 10 shot string grp size .7 vertical string


I still have several loads to shoot so we will see.

 

[River Man]

jwp475

I assumed from Hodgdons website that they still sold H870 since they listed recipies for it. I will probably try some H1000 instead since I already have some US869.

One thing I really like about the US869 is that it meters very well. I can drop a charge about 0.1 grain under and trickle in the last 0.1.


Boss Hoss,

Thanks for the recipies. You got some really high velocities out of your 27 inch barreled gun. Based on the velocities you are getting I am leaning toward cutting my barrel to 28 inches instead of 30 like I originally posted. One downside I learned about longer barrels is the guns won't fit in many cases. I plan on getting a Pelican or Storm case to tote my 300 Rum in. They are only 50 1/2 inches inside. This will limit me to 28 inches plus a flash hider and I will have one inch to spare in the case.

I plan to test 240 SMKs loaded with 98gr of US869 for accuracy soon. One group of three 240 SMKs I tested for velocity were 2965 fps +/- 10fps. The velocities ever very tight. I have not shot for groups yet. Base on the velocity consistincy the 240 SMKs should be accurate.

In an earlier post you alluded that you are a benchrest shooter. I have a question for you.

What is ES? I assume that SD is standard deviation but I have not been able to find or deduce what the acronym ES stands for.

Dennis

 

[jwp475]

ES = Extreme Spread

 

[River Man]

ES=Extreme Spread

None of my guesses were even close.

Thanks,
Dennis

 

[River Man]

H869 is too slow in the RUm with any barrel lenght when compared to Retumbo with a bullet as light as the 190 grain. Move up to ,say a 240 grain SMK and then h869 will give faster velocities than will Retumbo.....JonA got up to 3000 fps with H869 and the 240 SMKs about 200 fps faster than Retumbo ( if my memeory is carrect) Case capacity for the bore size and bullet is the determining factor for powder burn rate not barrel lenght..
I talked to Tye at Barnes yesterday about when all of the powder is burned and he said that he ands theier ballistics engineer have talked about this recently (they have read JBs article also) and they are not sure that the powder is completly burned in the first 3 or 4 inches...Tye is going to conduct a few experiments to see if he can get a better idea if this is true or not......

jwp475,

Has Tye at Barnes conducted any powder burn tests yet? I am interested in his results.

Dennis

 

[jwp475]

Tye has conducted some preliminary tests and the data seems to indicate that the majority of the powder is burned near the chamber...He is going to conduct more test but will be a month or so away.....

 

[River Man]

Come on guys, I need more of you to vote on barrel length.


I don't want to phone a friend!


Dennis

 

[jwp475]

30" was my vote and still is...........

 

[NYLES]

River Man,
I posted up 28" and would do it agian, I have a 270AM almost complete from Kirby that was originally gonna be a 28 however the barrel maker created issues with delivery and were dropped from the project...It will now have a 27" #7 Lilja 1-8 fluted and an edge break(they had it on the shelf). The guns main bullet will be the 169.5 Wildcat Im hoping for 3200-3300 fps using US 869 I have no Idea where to get WC870.

Anyway Free Run is North Yazoo City when it gets here maybe we can talk more shop and do a lil shootin.

 

[River Man]

I have never seen one of the AM cases. From what I have read about them they must be inpressive.

I would like to shoot with you sometime. I heard that there is supposed to be a 600 yd range in the Delta between Vicksburg and Greenville that some farmers set up. Would you happen to know where it is?

I am a member of Magnolia Rifle and Pistol Club in Jackson.

Dennis
aka: River Man

 

[River Man]

I forgot to tell you. Hodgdon no longer makes H870. US869 replaced it. You may still be able to get some surplus 870 but the supply has all but dried up.

The tests I ran with 869 and 240SMKs had an extreme spread of 20 fps. I think this is very consistent. My next test with the 869 will be for accuracy.


Dennis