Throat questions

[Yoda]

Seeing is how I'm bored out of my mind right now I pull my 25-06 out of the cabinet and started measuring things. Nothing fancy just old school, I've always shot 100gr flat base bullets, seated to the bottom of the neck of the case, well now that I'm playing with the 110 accbond with this new barrel that doesn't work, and even worse those AccuBond need to be seated
.050+ off the lands to shoot right and that puts the base of the bullet at or below where the where the shoulder starts from the main case body That's taking up some powder space. The throat length measurement comes out to .286, so I pretty much have then speed I want but pressures are at or near top end. I would really like to get that bullet out of the powder column to give me a bit of wiggle room. So question is jas anyone ever had a throat lengthened on a already chambered rifle, and if u did how did it effect things ? I have a ton of magazine length ( like 3.4) so that's not a issue..

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[TackDriver284]

If you have plenty space in your magazine to shoot the bullets long, then measure the chamber and find your longest OAL that fits touching the lands and see how much neck will hold that bullet at that measured OAL. I would not seat half a neck or less.

Increasing OAL decreases speed, where you can add more powder because you have less volume / pressure. I had this issue with my 7mm Magnum and 139 SST, until I increased the OAL .120" to touch the lands and increased RL-19 powder to match the speed. You may want to run a ladder test first to find your highest velocity / pressure.

 

[Yoda]

My col 3.238 touching, wouldn't shoot for crap till I pushed them in to 3.170 col

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[1Shot]

Off the top of my head I can't remember what the throat length is that I have on my 25-06. When I had it barreled the smith ask me what my intended use for this rifle would be, varmints with 100 gr or less bullets or larger game with bullets up to 120 gr. I told him larger game, white tail deer mainly. He said that he would throat it accordingly. He said that most of the reamers were cut for a throat that worked best with 100 gr. and lighter bullets. This was about 25 years ago. Your chamber might be cut for best accuracy with 100 gr and lighter bullets.
I just went to look up my data and I am loading a 117 gr Sierra Pro Hunter flat base bullet COAL 3.150 and this is 20 thousands off the lands. From your stated measurements it sounds like you do not have a short throat. I have not seen any of the Nosler 110 Accubonds but they must have a very long sharp nose to be loaded 3.238 COAL before the ogive touches the lands. You are jumping that bullet a mile at 3.170.

You did not mention what powder you are using. Might change powders or even primers and it will change how the bullet will shoot at longer seating depth. I have seen stranger things happen over the past 40+ years of hand loading. My current 25-06 has a SS Shilen #6 26" barrel on a Rem. 700 action. It does not shoot great with any boat tail bullets but it bug holes with most any flat base bullet. I have used the 117 Sierra Pro Hunter for a long time and it just works. I limit my shots on deer to not much over 500 yards because of energy drop off but out of hundreds of deer killed with it doing crop damage control for 15 years plus hunting in very liberal bag limit area for another 10 years I have never had to shoot a deer twice and 90% drop in their tracks and those that don't do not go far. I am shooting either IMR or Accurate 4350, they shoot the same point of impact with my load and average 3000 fps.

 

[gbflyer]

Yes you can. A precision throater is available for rent from 4D Rentals in Montana. Somebody here on the forum did one not long ago and did a write up on it. At least I think it’s this one.

Here it is:

viewtopic.php?t=39051

 

[joelkdouglas]

Yoda, I have considered throating out a couple rifles and in the end (once I considered the cost) decided it wasn't worth it. The gain might be 50-100 fps, and the cost is pretty high! Not to mention if you have a good chamber now, but the 'smith makes a mistake, they could ruin a great rifle.

My 25-06 loves the 110 AB, I wish Nosler produced them at regular intervals. I can get 3100 fps with 54 grains H4831 (the long cut version), and I can get 3200 fps with 55 grains RL26. I stopped at 3200 fps because I figured it was a safe load, I'm sure there's more speed there if I wanted to keep pushing. My 25-06 the throat is pretty short, the 110 AB and 110 ELDX are seated below the base of the neck, to the shoulder/case body junction.

Not saying you can't do what you want! If I were in your shoes I would try RL26 before I throated the chamber out.

 

[TackDriver284]

My col 3.238 touching, wouldn't shoot for crap till I pushed them in to 3.170 col

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Have you changed powders? Changing powders always worked for me when one type of powder has been tested long enough before giving up to move on to a different powder.

 

[Yoda]

The gun in question is a 1971 built model 700, the barrel it now wears is a Bartlein #3, 25 inches long. The powder I'm running is IMR 7977, fired by a WLR primer. I can seat a 100gr speer Bt Spitzer to the base of the neck and be a couple thousands off the lands, this bullet at 3400fps shoots better than my 60year old eyes and 9 power optics can hold it, ( it will hold a inch if I'm on my game). The old barrel that was on it was a 25 also, (built in that chambering) I bought the gun use in 95, and it hard a very Long throat due to erosion I do believe, shot prolly 99% of my deer with a 100gr Partition for the simple fact that is the only bullet that would stay in one piece at impact velocities inside 100yds. When I got the gun rebarreled I never gave bullet length a second thought, just told the Smith to cut a factory chamber, I am now dealing with my error, now that I want to move up to heaver bullets, case in point the 110 AccuBond it measures 1.195, and it appears from the folks on this site and what I'm seeing it needs a Ton of jump. I worked back to that 3.170 and it will do about a inch now at a solid 3300fps, but the base of that bullet now sits just below the should meets the case body, about a 1/2 inch of the AccuBond inside the case, and the 115 nosler BT is over a 1/2 inch.
I'm just looking at the possibilities of getting the heavier bullets out of the powder column, and was thinking lengthening the throat would do that..I've tried imr4831/ imr8133. The speed or accuracy want there( ran out of powder room with the 8133 with the deep seated bullets) and like the factory barrel this Bartlien barrel like to be run fast...

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[SJB358]

I think if you’re getting the accuracy you want and great speeds you’d be hard pressed to do much better by lengthening it.

Matter of fact, with the ogives like a Berger and the other super sleek bullets you may really like where your throat is at now if you have the twist to spin them.

 

[gbflyer]

On thing to consider is that the throat may get out where you want it within a few hundred rounds anyway. 25-06 is a pretty hot cartridge and can be hard on the throat. When you ream them long, before long they get too long![emoji1]

 

[Yoda]

It's a 1in 10, twist. Only reason I'd prolly shoot those other bullets would be just playing around. I'd look at the 115 or 120 Partition, before anything else, this is my main hunting rifle

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[SJB358]

I’d be okay with the set up if you’re getting the speed and accuracy you want. It gives you a little slack to chase the rifling a little as you wear it down.

 

[Yoda]

For the most part I am happy with it,

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[joelkdouglas]

Yoda,

I measured my bullet OAL and it’s just about the same as yours, 3.164.

What powder/charge are you using to get 3300 fps? That’s smoking!

v/r
Joel


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