SA 284 Winchester build driving me crazy

[J.Baker]

Yea it's a match reamer but hey now I know the difference in 284 win and 284 match so I guess I will have some jump but like you said my Weatherby has jump and it is 1/2 MOA
I guess I should have asked a few more questions and I would have went with different barrel I thought match was just a better grade
and this will be a hunting rifle and 3/4 MOA at 200 is better then I can shoot anyway.

I would guess James at NSS was talking about a Shilen Select Match grade barrel when you spoke with him, which is Shilen's top grade barrel. Not sure how Shilen grades their barrels, but I would guess the Select Match are those with the straightest bores and most consistent air gauge measurements.

The reamer used is a different matter. As I said previously, a SAAMI spec reamer will be have a throat length (or freebore length) for standard hunting ammunitions. A "match" or "long throat" custom reamer will cut a longer throat (or have more freebore) to allow for those longer match bullets. When it comes to the .284 based cartridges (6-284, 6.5-284, etc) most barrel makers will be using a match reamer with the longer throat because that's what 99% of their customers are wanting. The basic .284 Winchester can go either way as it's still a popular hunting round for those in the know and it's also popular with some long-range competitive shooters.

Best thing to do is contact the barrel maker directly and ask them what reamer they use.

Here's a shot showing the difference in length between the 140gr Nosler Partition and the 140gr Barnes TTSX bullet. Same weight and both are intended for hunting, but the TTSX is much longer because it's solid copper.