Remedy for Long Throat?

18 November 2003, 14:14

Jim in Texas

Is there anything I can do about an excessively long throat in a .270 Win? I originally had trouble finding the lands using the candle method. Eventually, I got a Stoney Point OAL gauge. With Nosler Ballsitic tips the COL to just hit the lands is 3.545. This measurement is consistent. However, Speer lists max COL at 3.340 and 3.380 is the longest COL that will fit in the magazine. This seems like I am excessively far from the lands. Is there anything I can do about this? Presently, I am just loading to 3.380.

18 November 2003, 14:30

ricciardelli

If the gun is shooting well, why worry about it?

18 November 2003, 14:31

redial

You could have the barrel set back and rechambered almost any way you like, pretty inexpensively.

Another thing I've stumbled on as a target shooter is moly bullets. Many of mine seem to like a loooooooooonng jump into the leade of 50 thousanths or so! Skeery. Moly may or may not be appropriate for a hunting rifle, depending on what you do with it but it's something you might try.

Cheers!

Redial

18 November 2003, 14:35

Jim in Texas

It is not shooting as well as it should. I am not getting better than 2" groups at 100 yards.

18 November 2003, 20:32

Brent Moffitt

Set the barrel back and rechamber with a reamer that has a shorter throat, or one that uses a seperate throater to finish the job.

Rechamber for a longer cartridge, 270/300 Ultra Mag maybe. [Wink]

Really heavy Sierra bullets might get you closer to the lands, might even fins a good shooter out of them too.

19 November 2003, 02:40

Hot Core

quote:
Originally posted by Jim in Texas:
Is there anything I can do about an excessively long throat in a .270 Win?

...With Nosler Ballsitic tips the COL to just hit the lands is 3.545. This seems like I am excessively far from the lands. Is there anything I can do about this? ....

Hey Jim, Yes.

1. Find out how long the opening in your "magazine" is. If your 3.545" cartridge will fit in it, you may not have a problem at all.

Or if the magazine is a bit shorter (say 3.5" as an example only) try Seating the B-Tips to 0.015"-0.020" short of that length (3.485"-3.480").

Of course, you will then need to re-develop the Load from below in either situation.

2. Use a Bullet that is not as sleek as the B-Tip. Pick something with a lower Ballistic Coefficient(B.C.) because the profile of their "Ogive" will touch the Lands before a higher B.C. Bullet will touch.

For example, if you try one of the Speer Bullets from your Manual, you "may find" the problem is resolved. Try the Grand Slam which is a fine Bullet. Or use a non-plastic tip Hornady or a Sierra.

I like the Nosler B-Tips myself and occasionally use them, but if they are a problem in your rifle, don't use them. All the other regular old Bullets will kill Deer just fine, so don't let that be a concern.

Yes, the Lower B.C. Bullets loose velocity a bit quicker than the Super Sleek ones, but at the distances a 270Win is useful, you will have PLENTY of retained Energy at the Point-of-Impact.

3. Depending on how many Bullets have been down your barrel, if it was shot when the barrel was very hot or if you are running Full Throttle Loads, your Throat(distance to the Lands) may have receeded a bit.

This still may not be a problem with the "Lower B.C." Bullets. If it is, then you either have to keep working with it until you develop a good Load with some jump, have the Chamber re-cut (you can do this for the specific Bullet you want to use), or re-barrel.

One of my rifles shoots a specific Bullet extremely well when it is Seated 0.265" Off-the-Lands. No typo - more than a 1/4" jump. (It isn't a B-Tip.)

4. You could use it as a Single Shot if you absolutely positively just HAVE TO USE those B-Tips. Seat it on out just short of the Lands and re-develop from below.

This is not as much of a handicap as some folks would think in a non-dangerous Game rifle. Over almost 5 decades of hunting, a single shot "might" have cost me 2-3 Deer, or maybe not at all. Had I been using a Single Shot, I'd have been mentally prepared for the Second Shot and been ready to load it quickly. If you haven't hit it on the second shot, you need to STOP and see what's wrong rather than continue flinging Bullets anyhow.

When I have used a Single Shot, the problem of needing a Second Shot never came up.

...

The Overall Cartridge Length listed in a Manual for the 270Win is only telling you what they used in their firearm and should be considered as a "Guideline" or "Extra Info" only.

It is a bit more difficult to get any of the Super Sleek bullets started straight into the barrel, if you can't set it out far enough.

Good luck to you.

19 November 2003, 08:53

Brent Moffitt

An extended magazine box such as Wyatt's would give you almost an additional .100" in length if that's what you need. George Gardener at G.A. Precision will install one of these if you don't want to. [Smile]

I like .015" - .020" tip clearance at the tightest point in the mag box.

Single feeding them will tell you if you'll find an accuracy gain seating on the lands, or closer to them than you magazine box allows.

19 November 2003, 09:23

Jim in Texas

Thanks for all the advice and information. Since I am almost .2" from max. magazine COL to COL to the lands, I think I will have the barrel set back.

20 November 2003, 12:57

Swany

Jim, have you tried to set it to the minimum and boost your loads way up. Lot of times this works, also, I you could go to the nosler partition in a semi spitzer which would likely reach the lands. I had a weatherby in 270win, and it also had the excessive throat, with the 150 partitions it grouped real well with the bullet seated in a minimum and a case full of H4831, with mag primers.

20 November 2003, 13:13

bartsche

It may not be what you want or do the trick but the 170gr. Hornady round noses when seated out to a max. Magazine length. might come close to touching the rifling. Just a thought.roger

20 November 2003, 19:38

<Pablo>

Before you start rechambering, how does it shoot with the bullet seated to touch? Your barrel may not be any better than a 2 incher! You might be better off wit a new barrel, could save you a few bucks in the long run.

21 November 2003, 01:53

B17G

To me a long throat is a good thing, more velocity (if you need it) and more accurate at lower pressures.

Brent's suggestion about a longer magazine from Kevin Wyatt is an inexpensive idea. ( I know Kevin, and he does EXCELLENT work on anything).

Pablo's suggestion also about seeing if the barrel is a better shooter than 2 inches to begin with. I hope that long throat is not a product of throat erosion, If so the turn back of the barrel and rechamber are the best alternative to just getting a new barrel put on her.

Good luck with the project.
[Razz]

21 November 2003, 04:21

<Savage 99>

quote:
Originally posted by Pablo:
Before you start rechambering, how does it shoot with the bullet seated to touch? Your barrel may not be any better than a 2 incher! You might be better off wit a new barrel, could save you a few bucks in the long run.

This is the best idea so far. One must be scientific and there is no proof that the distance to the lands has anything to do with the groups.

In fact there are many things that have a much greater effect such as bedding, loose stuff, bad barrels etc.

Another bullet that may reach the lands is the Failsafe.

21 November 2003, 05:17

cummins cowboy

I recently checked my late 80's rem 700 adl 270 with a stoney point gauge right before hunting season to get it ready, with the nosler ballistic tip and the hornaday interbond in 130 grain, the bullet would have to be seated 1/8" out of the case in order for it to touch the lands. I also think my throat is excessive, but took it out the next day with the hornaday interbonds the average of my 3, 3 shot groups was .80, good enough for me and the deer sure thought it was pretty effective too.

21 November 2003, 07:38

Cal Sibley

I've never done this, only read about it. With some magazines you can file down the front lip allowing you to use longer bullets. I'd give some thought to it. I recently measured some loaded rounds for 11 different calibers and numerous bullets with my Stoney Point OAL guage.
Some of the OAL's are ridiculous. Some bullets don't even come close to the lands. Apparently SAAMI specs don't mean much to the manufacturers. Best wishes.

Cal - Montreal

22 November 2003, 01:02

John Frazer

Before you think about spending a couple hundred bucks to rebuild the rifle, there are some more basic questions:

1. What make of rifle is this? Some manufacturers use very long throats. I have two Mark X Mausers in which it's impossible to come near the lands with any bullet. One shoots acceptably well with some loads. The other shoots very well with almost any reasonable load.

2. Have you tried any other bullets?

3. Have you checked your cartridges for concentricity -- even neck thickness, low neck and bullet runout?

4. What kind of stock does your rifle have, and how is it bedded? Screw tightness OK?

Almost any of these (except a totally new stock) will be easier and cheaper than setting back and rechambering.

John

22 November 2003, 02:20

Soundman

Isn't this what Weatherby calls "Freebore"? At least they charge for it!

If it ain't broke, don't fix it.

Mike

22 November 2003, 05:54

Sabot

Try some Hawk bullets and just seat them to a length that works in your existing magazine. Hawks are soft annealed pure copper jacketed, and slug up like no other bullet made. In addition, they have gentle ogives, which puts the lands contact point further forward on the bullet. They are famous for shooting well in shot out bbls with long throats.

Last, but not least, they are LETHAL!! They expand to 3X and will not, repeat NOT, come apart.

25 November 2003, 17:04

Atkinson

I like a long throat in my rifles..I can seat the bullets way out and get more powder in and more velocity and less pressure...

A prime example is the wonderfull Brno Mod 21 and 22, they have the longest throats you will find anywhere and they ALL shot great...

An interresting article in A-Squares manual on long throated rifles, sometimes mistakenly referred to as free bore..

Also goes into funnel and stright throats, and the funnel throat can be problematic apparantly.