Trying to work on a load for a browning abolt 300 rum? Questions! Lots!

[huntxtrm]

Here is the stuff I'm working with. Browning a bolt 300 rum. Factory rifle, except for a Timney spring and a muzzle brake.

Magazine length is 3.634 +/-
To the lands of the rifling is 4.092. Almost 1/2" of freebore, if I keep them in the mag. I am loading berger 215 hybrids, for long range hunting. With retumbo, and cci magnum rifle primers. Looking at starting with 81 grains and moving up? Should I just stick with 3.6 in col, and just play with the powder charge to get accuracy? That's about all I can do, as far as I know. And please forgive my ignorance, I'm new to reloading. I am taking it one step at a time, safe and slow. I would like to get the most accuracy possible out of this rifle, as is for now. Using the mag. Oh, and full length size, or neck size? I've read the latter is better, in the hornady book. I would appreciate any knowledge, anyone could provide. Thanks in advance.

 

[Nitroman]

In my Tannel built 700 using Nosler brass my base to ogive is 2.971" and touches the lands. Base to tip using Berger 210 OTM bullets that I tipped is 3.616" exactly. I have about 0.065" left in the magazine. I wanted the tips of the bullets to almost touch so during recoil they wouldn't build up enough momentum to drive the bullets into the case.

I'm using PressureTrace and found my starting load of 89gr Retumbo gave me 3075fps ave at 53kpsi, 90gr. 3120fps at 56kpsi and 92 averaged 3150fps for three rounds at 58,500psi. I am looking at the primers right now and cannot tell the difference between the 80 and 92 grain loads. These are Fed 215m Match.

Note: my barrel is 29 5/8" from the face of the receiver to the muzzle crown so you'll have to subtract ~25-30fps for your barrel.

You have to work with what you have. If you rebarrel you can have the chamber set up to suit your rounds. Load long and start reasonably low for now and see what happens accuracy-wise. Once you find a velocity, then work with seating depth. Don't bother neck sizing unless you are using fired brass in your rifle. Very carefully inspect the fired cases to see if there is any deformation to the bases. I had a Mod 70 chambered in .300 RUM (wish I'd kept it), that had a distinct bulge at the bases of once fired cases.

 

[huntxtrm]

In my Tannel built 700 using Nosler brass my base to ogive is 2.971" and touches the lands. Base to tip using Berger 210 OTM bullets that I tipped is 3.616" exactly. I have about 0.065" left in the magazine. I wanted the tips of the bullets to almost touch so during recoil they wouldn't build up enough momentum to drive the bullets into the case.

I'm using PressureTrace and found my starting load of 89gr Retumbo gave me 3075fps ave at 53kpsi, 90gr. 3120fps at 56kpsi and 92 averaged 3150fps for three rounds at 58,500psi. I am looking at the primers right now and cannot tell the difference between the 80 and 92 grain loads. These are Fed 215m Match.

Note: my barrel is 29 5/8" from the face of the receiver to the muzzle crown so you'll have to subtract ~25-30fps for your barrel.

You have to work with what you have. If you rebarrel you can have the chamber set up to suit your rounds. Load long and start reasonably low for now and see what happens accuracy-wise. Once you find a velocity, then work with seating depth. Don't bother neck sizing unless you are using fired brass in your rifle. Very carefully inspect the fired cases to see if there is any deformation to the bases. I had a Mod 70 chambered in .300 RUM (wish I'd kept it), that had a distinct bulge at the bases of once fired cases.

Do I need to get me a chrono, if I'm going to get exact? I am shooting once shot brass, shot from this rifle. I read in Hornady that it made the head spacing more exact, if you only neck size. It also said it would increase case life and accuracy? Is this true? I will only be loading them for this rifle. No one elses.

 

[Nitroman]

A chronograph is a tool to help you when setting up your loads. I consider it so essential I will not shoot any rifle of mine when using new loads. You don't have to break the bank, a plain Shooting Chrony will get it done for about $105.00.

Yes, neck sizing will help your brass, to a point. At some point you should anneal the shoulder area and you will also need to bump back the shoulder once you begin to feel resistance to chambering.

But these are for the future. The Chronograph will tell you how fast your bullets are so you can compare your loads to book.

Load some low and put lead downrange to see how your rifle is working. People reloaded for many years without chronographs.

 

[huntxtrm]

A chronograph is a tool to help you when setting up your loads. I consider it so essential I will not shoot any rifle of mine when using new loads. You don't have to break the bank, a plain Shooting Chrony will get it done for about $105.00.

Yes, neck sizing will help your brass, to a point. At some point you should anneal the shoulder area and you will also need to bump back the shoulder once you begin to feel resistance to chambering.

But these are for the future. The Chronograph will tell you how fast your bullets are so you can compare your loads to book.

Load some low and put lead downrange to see how your rifle is working. People reloaded for many years without chronographs.

Thanks for the info. I will get startted

 

[huntxtrm]

Should crimp? Or not crimp? If I'm loading into my magazine.

 

[Nitroman]

You should have enough neck tension to not to have to crimp. Drop one into the magazine and fire a few rounds over it. If the bullet moves, then you know you have to crimp.

 

[huntxtrm]

Thanks for the info. I will get startted

You should have enough neck tension to not to have to crimp. Drop one into the magazine and fire a few rounds over it. If the bullet moves, then you know you have to crimp.

Thanks for the good advice. That should get me to the range. I really appreciate it.

 

[Nitroman]

Thanks for the good advice. That should get me to the range. I really appreciate it.

No problem. Everyone started somewhere.

 

[huntxtrm]

You should have enough neck tension to not to have to crimp. Drop one into the magazine and fire a few rounds over it. If the bullet moves, then you know you have to crimp.

Got some loaded as follows. All have cci large rifle magnum primers 250. All are COL 3.61 That the longest that will fit in my mag with a weee bit of clearance. Berger 215 hybrid targets.

5@ 81g 2 to dirty the barrel.
3@ 81.5g
3@ 82g
3@ 82.5g
3@ 83g



Starting low and safe. Got the min load from a post on here, someone got from berger. 90.2g is listed as the max load. I haven't went that far yet.

I have some concerns, someone might fill me in and make me feel safer about it.
If you look at the pic, you can see these bullets are so long, they seat deep into the case at my COL. Is this safe? Or should I go with a shorter bullet, and forget about the Hybrids? If this is normal, I'm going to the range and start grouping!

 

[huntxtrm]

 

[huntxtrm]

That is the rifle I'm hoping to shoot them out of.

 

[huntxtrm]

I have lots of room in the action for long rounds, I would just have to single shot them. If someone thinks I should go that route. When I push a bullet in an empty case to the lands, it measures 4.092! Lots of freebore! I recon!

 

[huntxtrm]

The above question might be ignorance on my part. The Berger load data says COL of 3.600, so if must be good. But I would still appreciate reassurance. I like my face the way it is, don't look to good, but it all works! LOL