Thread: Remington 700 Sako and M16 extractor conversions

This thread is following on from the thread started by Kiwi Greg in buy, sell, swap that then got shifted to his commercial section. In it he claimed that M16 extractor conversions on Remington 700’s for the Lapua magnum case were safer than the Sako extractor conversions. I asked him to clarify this, which he hasn’t done. So here are the pros and cons in our opinion based on having fitted and used both systems for some years now.

As can be seen from KG's links most if not all of these Sako extractor failures due to complete case head failure have been in benchrest or standard head size cartridges. There have been no instances with the Lapua magnum case that we are aware of. Case head diameter has nothing to do with it. If you are stupid enough to overload a Lapua magnum case to the point you get complete case head failure, which will be in excess of 90,000psi, the extractor issue will be the least of your problems! With a catastrophic action failure in a Remington you will almost certainly have copped other parts of the action or barrel, potentially even the bolt itself. The Lapua Mag brass has such a reinforced web of extremely hard brass that it is not necessarily the weakest link in the chain any more as with ordinary brass. That is why you cannot use conventional pressure signs as indicators when working up loads with this brass. And if you really think the tiny roll pin that retains the M16 extractor is going to resist this sort of pressure I think you’re fooling yourself, especially when the much longer length of the M16 gives the escaping gas more leverage on this pin anyway. There may be some argument that the M16 extractor retaining pin will withstand the much lower case head failure pressure of the PPC and similar comparatively weak brass, which is where this very rare Sako extractor issue first arose.

Tikka has used this exact same Sako extractor system for years, and there’s been no wail of terror from T3 users!

Action strength wise verses the extra bolt thrust due to the larger diameter case head, the main issue with either of these conversions is the way the lower locking lug is undercut reducing its shear strength. The standard M16 extractor requires an even deeper cut than the Sako extractor, reducing lug shear strength even more. This would be more of an issue with the extra bolt thrust from the extreme pressures involved with a Lapua Magnum case head failure. Recently narrower width and depth Sako and M16 extractors have become available that reduce the amount this locking lug is undercut, making this less of an issue.

Another disadvantage of the M16 extractor is that it needs more barrel counterbore clearance to hop over the case rim, about 40 thou or 1mm. This means the counterbore needs to be 90 thou or over 2mm bigger than the bolt nose diameter. One of the often quoted strengths of the 700 action is the 3 rings of steel around the case head - the bolt nose, the barrel counterbore, and the front receiver ring itself. But all of these are pointless if you have to run extra clearance between the bolt nose and the counterbore, negating the other 2 rings of steel. This is more of an issue with the Lapua magnum head size, as after you open the bolt face up, you end up with a very thin rim remaining around the bolt nose. With the extra clearance required with the M16 conversion, there is even less support for this rim, and a flying piece of this wouldn’t be much fun either.

We have come up with a system we’ve been using for our Sako and M16 extractor installations that solves all these extractor captivation issues, but the standard gunsmith barrel installation certainly won’t go to this extra effort and expense.

As with most things, if you exercise common sense and reasonable caution in your reloading, you’ll be quite safe with all these conversions. Just don’t go chasing some of the silly over the top velocities posted on the web at times. Stick to load info from reputable sources you can trust and you won’t get into trouble!