Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpose?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by cdherman, Sep 1, 2013.

  1. cdherman

    cdherman Well-Known Member

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    Working on a friends 700 Rem BDL, 270 Win. Gun's perhaps 4 years old, maybe 5 from date of manufacture. Perhaps 100 rounds down the barrel. Purchased new by my friend.

    Groups with factory Rem Corelok ammo were miserable, perhaps 2" at best, off a shooting rest, and with experienced shooters. The trigger is not the best, but the rest negates poor trigger, and to a certain extent scope. Scope is a Nikon Prostaff. Not fabulous, but not crap either....

    I "borrow" the gun to hand load something special to remedy the problem. First debate is whether to float the barrel or not. I decide to float. No, I did not bed the action. Lot more work, though I might do that too, if needed. But I contest that floating and/or bedding is not the issue...

    I measure the base to ogive measurement using the Hornady Lock-N-Load OAL device (its not really OAL, but that's what they call it) with several common 270 bullets and I am shocked. The throat is at least 1/2" I cannot seat130gr Sierra Game Kings, Hornady Interlocks, Berger VLDs, or Nosler Ballistic tips anywhere CLOSE to the rifling. We are talking 300 thou jump, in order to get at least .277 of bullet (usual recommended min seating depth) in the neck.

    This gun has Weatherby style throat. (We are working on his 340 Wby as well).

    So I load some Nosler Ballistic tips and some Sierra Gamekings to a pretty random COAL, that put about diameter (.277) in the necks, spread out a test series of H4831SC in each and went shooting. (cases were well prepped, sized down 3 thou, primer pockets reamed, flash holes reamed etc)

    Results: Groups were better. But showed no predictable pattern. About 1.5 - 1.75" 3 shot groups. Across both bullets and all powder ranges. Makes me think I have a variable that I am not accounting for.

    So a couple of questions and points to debate:

    1) In a long throated gun, particularly a 270, does anyone have a bullet that we should try? The magazine seems to be generous -- we could seat bullets longer, but I am running out of neck before I run out of magazine.

    2) Why is this happening? I have loaded for many Rem BDL's, including at least one other 270. All had throats that I could measure (some the old way, with a fired case, and smoked bullet, or a lightly crimped bullet). This one is LONG. I have a theory, and it troubles me: The lawyers at Remington said to the engineers; "You need to make it harder to blow up the gun". And the engineers, knowing what sorts of loads are in books and on the internet, said "If we make the gun with more free bore, even excessive charges will never produce dangerous pressure, since it will be impossible to load to the lands". I admit, conspiracy theory. But a couple Google searches reveal we do not have the only long throated BDL here.....

    OK, so your thoughts????
     
  2. cookjp

    cookjp Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    I have a Remington 700 bdl 270 that I bought in the late 90's that is the same way. I tried to seat my 130 BT to the lands and the bullet would be all the way out of the case. I ended up seating the bullet into the case enough to fit in the magazine and to ensure that I had enough neck tension to hold the bullet in place. I then fiddled with the powder charge to get the desired accuracy and was thankfully able to meet my expectations. I did find that a Lee factory crimp die helped to improve the overall consistency of my loads and since this is a hunting rifle and the rounds would be handled roughly it made me feel better to crimp them. You mileage may vary though. I however have not been able to get any other bullet besides the 130gr Nosler BT to shoot worth a crap, good thing I like them for deer.
     

  3. idaho elk hunter

    idaho elk hunter Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    Its called freebore. It will lower pressures in factory ammo and allow reloaders to get more velocity by working their loads higher. Most think it degrades accuracy. If you know how to load for it its great! Use 4350 or 4831 and a 215 or win mag primer. Use very hard bullets, I typically use Barnes, any thin skinned bullet typically will not shoot worth a darn. Try 140 through the 160ish gr bullets and see which work best with your barrel/twist rate. Make sure the barrel is perfectly clean before switching to these bullets.
     
  4. J E Custom

    J E Custom Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    According to SAAMI Specs. .300 thousandths is max freebore including the lead angle of less than 1/2 degree.

    The 270 was in reality the first magnum with pressures to match. So yes they did it on purpose.

    Freebore is not the enemy.

    Bullets like the partition have a long bearing surface and will improve the neck to bullet Engagement
    when seated to magazine length.

    J E CUSTOM
     
  5. cdherman

    cdherman Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo


    So are you suggesting that if indeed the freebore (or throat as I refer to it) is longer than .300", it is out of SAAMI specs?

    That also is interesting, though does not make much of a difference really. With regards to legal implications -- a gun that is outside of SAAMI specs, but actually is "less dangerous" than SAAMI specs could never be held up to a product liability lawsuit.

    Remington could wander outside of SAAMI specs so long as they have good evidence that their non-conformance to SAAMI results in a less "dangerous" gun.

    Albeit, less accurate....

    .........................................................................................................................

    Topic long free bore/throat. I agree that a bullet with a flat base would give more seating. I need to get some Barnes bullets and see how they react. I was not aware that perhaps the long throats in 270 win had been there for a long time. Maybe, this is an issue that has been there forever, but only noted as more efficient means of detecting the distance to the rifling has been available.....
     
  6. MudRunner2005

    MudRunner2005 Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    My best friend has an old Rem 700 .270 Win, that he's had since new (15 years now). It has the same long free-bore in the throat.

    Like JE said, freebore is not your enemy, and can be your friend if you know how to load for it.
     
  7. cdherman

    cdherman Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    I've been reading a lot more, all over the web, places like TFL, Highroad, etc...

    Seems my suspicions are common that gun makers have lengthened the throat/freebore in recent years.

    And I am not alone in having trouble with accuracy.
     
  8. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    Very well said

    Your initial statement of the rifles condition made me cringe, here is what I have pictured in my head. Factory rem 700 with a pencil weight barrel that needs contact at the tip. Over torqued into a cheep plastic stock, strapped into a useless "lead sled" eliminating the rifles ability to recoil and a bunch of guys thinking that this negates the fact that the trigger sucks, the whole time firing to fast and letting the barrel overheat and the groups suffer.
     
  9. cdherman

    cdherman Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    Its a BDL with a nice wood stock, and the screw are not over tightened (though with wood stocks its always a bit of a crap shoot till they are pillar bedded). I shoot with a sled, but the gun is not strapped down, no contact to the barrel at all and the gun is allowed to jump some though I hold stock. Its pretty much the same form I use in the field.

    At the range where I shoot, the have cease fire every 15 min, and takes about 3-4 min. In the remaining 12 min, I shoot 6-8 shots. The barrel gets hot, but not crazy hot. I can hold it with no discomfort.

    As for trigger, aside from esoteric discussions of lock time, if I can manage to squeeze with the cross hairs dead on, and that's the last thing I see, before the flash and muzzle jump, then I cannot agree that the trigger is the cause.
     
  10. Trickymissfit

    Trickymissfit Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    at onetime I had a Remington 700 in 270 Winchester. I remember that the head space was very tight (on the minimum side), but the chamber itself was a little over .070" too long for the neck length. Plus side here was that I never had to worry about brass flow! In those days I never had a good way to measure the throat length, but would have guessed it to be around .35" too long at the max and probably closer to .275". The rifle shot well, and would do sub one inch groups all day long (it was built in the late 1970's or very early 1980's). Didn't like any 150 grain bullet I tried, and settled on 130's. But ended up with about a one caliber jump at best! Now I have a Weatherby in 270mag, and believe it or not they seem to have similar throats to that old 700 Remington! (.300 to .375" range). I kinda wonder whatkind of a throat the 270WSM has?
    gary
     
  11. cdherman

    cdherman Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo


    I had a 270 WSM in A Savage FVSS 16 heavy barreled varmit version. For LARGE vamits with antlers. It had a much more sedate freebore, as I had no trouble seating to the lands and getting the cartridges to fit in the magazine.
     
  12. J E Custom

    J E Custom Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo


    We brought a lot of this on ourselves because we wanted "More Velocity" So in order to stay with the market trends Almost all of the newer cartridges have more free bore. So they boosted the pressure from 55,000 average to 65,000 PSI. In order to do this they had to add more free bore.

    All of the WSMs, SAUMs, RUMs have At least .200 thousandths free bore or more.

    When Winchester came out with there 270 Average pressures went from 46,000 - 52,000 to
    over 55,000 so they increased the free bore to manage pressures and limited the mag length
    to prevent loads that could reach the lands making pressures exceed max.

    Roy figured this out and decided to make all of his rifles with lots of free bore in order to gain velocity
    over everyone else. Because Velocity sells.

    To address the accuracy issue there are a few different rules to get the desired accuracy from a
    belted case with lots of free bore.

    1= The chamber must be perfectly aligned with the bore centerline.
    2= The action and bolt must also be square and on the same centerline as the chamber and bore.
    3= Head space with a belted case should be the minimum (Just enough to close the bolt) If there is
    more than .001 or .002 thousandths head space the need to fire form becomes very important.
    4= Once the case has been fire formed, sizing correctly is the secret to accuracy (Only size enough to close the bolt "No More") . when you size to the minimum you are essentially shooting a shouldered case because it is head spacing on the shoulder and with Zero head space the case fits the chamber
    perfectly and is aligned perfectly with the bore. The bullet will still be held centered by the case even
    after it reaches the lands and starts to engrave.

    Back in the day we had to seat the bullets where they touched the lands in order to make up for the
    quality of chambers, Reamers, brass, bullets and in general, workman ship. Now with all of the improvements in all of the above, It is easy to achieve outstanding accuracy.

    1/2 MOA groups are a starting point now days with these cartridges and Sub 1/10 th MOA groups are possible and not to uncommon.

    The 270 Winchester is a fine old cartridge and very capable of 1/2 MOA @ 600 yards. especially now days.

    Sorry for the long post.

    J E CUSTOM
     
  13. cdherman

    cdherman Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo

    What if the bullet exits the case neck before it reaches the lands? This is what is happening in the WBY 340 I am working on. At least with boat-tails. Seems to me then, that the bullet has a very real chance of skewing in the freebore region, especially if that area is cut loose and not to tight specs.

    I do appreciate the long post. Points #1 and 2 are out of my control in a gun I do not own, #3 does not apply to the 270, and #4 is exactly what I do with my guns. I have a nice 7mm SAUM that I have shooting about .5" groups. Only thing custom is the Shilen barrel I screwed in. And I guess the pillar bedding I did myself......

    I have perhaps been lucky to never have to deal with this much freebore before.
     
  14. Tikkamike

    Tikkamike Well-Known Member

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    Re: Anyone deal w/700 Rem w/long throat? New gun, not shot out. Rem do this on purpo


    Spot on! barnes typically excell in freebore chambers. I bet a group shot with barnes TSX will change this story a lot