Forums.NitroExpress.com

Bwana,

your Merkel is a stout gun and will eat FMJ as well as Barnes.

If you reload, you can drastically minimize possible ill effects from hard bullets, by the way:

Hard bullets create a steeper initial pressure curve then regular bullets because of increased resistance to engraving. If the dimensions are off only by a little, they can cause pressure spikes which can subsequently damage the gun. Because of this, all mono-metal bullets and most steel-jacket FMJ are either undersized or have some kind of drive-band design that minimizes the contact area (and hence the resistance to engraving and the danger of pressure spikes as a result of wrong bullet dimensions).

Therefore:

1) As you already use a bullet that makes the pressure curve steeper, use a powder that counters that effect, - a slower powder. In a .470 NE, that would mean to stay well clear of the popular RL-15 (a fast powder) when using hard bullets. Go one or two steps slower, for example by using Norma 204, Hodgdon 4350 or RL-19.

2) Measure every single bullet with a micrometer or good caliper (and preferably with a bullet comparator as well) and toss 'deviants'.

Too much work? Benchrest shooters do this all the time, and for good reason: You would be quite surprised how many bullets, even within match bullet lots, are off dimensionally - an occasional one by quite a lot. It is not just the variation in width that is an issue: Often there is a downright irresponsible difference in the distance from bullet base to ogive from lot to lot - especially when bullet manufacturing dies have been changed (ogive to be understood as the point where the bullets body will engage the rifling when fired).

Now: A lot of older guns especially are neither CIP or SAAMI standart in the throat area, which means that some published OALs or even factory loads might put the ogive dangerously close to or even into the lands. Add to that some unexpected variation in the bullets dimensions, and you can have very serious problems. A round that was meant to be started off the lands can easily damage or even blow up an older gun when jammed into the lands, especially when a fast powder and / or a hard bullet is employed on top of that. Publishers of loads and some manufacturers of factory ammo for African calibers tend to take big liberties with OALs (and hence the jammed bullets seating issue) anyhow. I learned the hard way by shooting factory ammo from a well-known company in my .404 that made my gun fly over my head backwards. It turned out that the WoodIeigh softs of that load were seated well into the lands. Had that not been a modern gun with safety gas vents and of very solid construction it would have blown up. Therefore, I can only advise everyone who shoots nitro calibers to check where your bullet sits relative to the rifling (by using the Stoney Point /Hornady device, for example) EVEN WITH FACTORY AMMO AND ESPECIALLY WHEN SHOOTING FMJ AND MONOS.

Post Extras