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> Long throated 30-06 ?
Long throated 30-06 ?
@ 10:46 am (GMT) |
Rafal PisulskiHi,I'm starting new realods for my R700 LR in 30-06 with sierra 195gr TMK bullets. Knowing ttaht it is long bullet and 30-06 is not so generus in free bore departmnt I have measured max COAL using lightly sized case. Result is 89,68mm when optimum OAL with boat tail at neck edge is 87,72mm. So 2mm jump with looong bullet. That is normal or it is realy long throated rifle? All best, Rafał |
Replies
@ 07:28 am (GMT) |
Nathan FosterRe: Long throated 30-06 ?Hi Rafal, within a min SAAMI spec chamber, the OAL for the 195gr TMK is 86mm touching the lands.In a max spec chamber, the OAL is 89mm to about 89.1mm. Your chamber obviously beyond max. I have been seeing such specs within the Remington's for some years now. Not to worry. To avoid confusion, make sure that you have put a lot of time into prep. Make sure the rifle passes the 1 oclock test as described in the book set, the mag box not pinched, make sure the trigger is fit for purpose. Check over the scope mounts. Break the barrel in using basic ammo and monitor the rate of copper fouling (see video learning tab - trouble shooting the M700). Attend to the bore as required. Once you are have the basic variables under control, then finally you can look at reloading cause and effect, without being confused by other issues. At this point, try your basic load work up at your 87.2mm depth. Consider using a double base powder for maximum power. If using a single base extruded powder, look for sweet spots around 2500 to 2650fps. If using a slow burn double base, look for sweet spots anywhere from 2600 to 2750fps. If the loads are not accurate, try 88mm. It won't form a donut in the case neck with a single round of load development. A donut will only form in the neck following repeated loadings with the bullet sitting out in the case neck. And yes you can try seating even deeper (e.g. 86.5mm) if need be, but lets see how this initial work up goes. The barrel of your rifle is quite heavy and the bullet will not be going extremely fast so hopefully it produces consistent vibrations and is not overly sensitive to exit timing / 'when' the bullet leaves the bore. The Sierra bullets do vary a bit from one to another. Pick one, mark the tip with a marker pen and use it to set your depth, then put it aside. Do not try and make all the loaded bullets the exact same length as they will vary. Just use the dummy (the bullet you are currently using for quoted measurements) and then leave the die at that setting. Remember, if this were a .308, a 2.5mm jump would be the norm, also producing roughly the same speeds. All the best. |
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@ 07:52 am (GMT) |
Nathan FosterRe: Long throated 30-06 ?P.S, please note that there are major differences between the neck diameter of U.S brass versus Lapua, should you intend to use this. The Lapua brass only gives around .001" (.025mm) to .002" (.0508mm) chamber clearance and can jack up pressures (spikes) in some rifles / depending on chamber dimensions. This can be useful in max spec chambers (if the max spec involves diameters) but is otherwise problematic in modern sporting rifles.If possible, try to obtain an accurate measurement of fired case neck diameters versus loaded ammo (see also test at the end of my youtube video - is it me or is it my rifle). If your fired cases are only a couple of thou over loaded ammo neck diameter specs, then act with caution as the rifle will be liable to produce high pressure as you work up loads. Remedies include either neck turning or changing to another brand of brass. One should also be aware of the effects of using a suppressor in conjunction with heavy walled brass - not a good idea. This is otherwise a complex subject sorry. A .30-06 chamber neck needs to be relatively loose for the sake of heavy wall mil surp ammo (still in circulation). Heavy wall sporting ammo brass duplicates original specs and can help take up any chamber slack. But heavy wall brass can also limit breathing space in modern rifles reamed with modern reamers. Provided loads are mild, such things normally go unnoticed. But when searching for high speeds, heavy cases can ruin your day. There is no complete fix (reamer design level) for this. One must instead select components accordingly. |
@ 08:58 am (GMT) |
John StewartRe: Long throated 30-06 ?I have a Remington 700 in 30-06, it also has the long throat and it makes it easy to set the bullet way out and make room for powder. |
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