Hi guys, my name is Pablo. <SNIPPED STUFF> Recently I bought a Bergara B14 HMR and 6.5 chambered (twist 1 8"). <SNIPPED STUFF> 1. Which bullets do you recommend? I think in 140 grains, and about the brand I think Sierra. 2.How much grains of powder per cartridge I will need? Nobody has this rifle here in Spain so to start is very difficult. 3. More advice? <SNIPPED STUFF>
Welcome Pablo! Spain is a beautiful country with wonderful people. It is nice to hear from you. I hope you do make it back to the USA. We love enthusiastic shooters here!
You are on the right track with SIERRA and BERGER bullets. They are both capable of a high degree of accuracy and are well made products. But in the 6.5mm range, the Hornady ELD-M bullets are also very good, if you can find them. As you said, bullets in the 140 grain range are going to be 'best' for long range shooting.
In the SIERRA bullets, I would start with the 6.5mm, 142 grain MATCHKING HPBT (hollow-point boat-tail), which is Sierra product (SKU)#1742. It has a G1 Ballistic Coefficient (BC) of 0.595. They says it needs a 1 in 8" twist, which you have, so that works fine.
In the BERGER bullets, I would go with the 6.5mm, 140 grain, LONG RANGE BT (boat-tail) TARGET bullet (SKU: 679459264099). This bullet has a G1 BC of 0.593 (and a G7 BC of 0.304.) Berger recommends a 1 in 9" twist or faster, so again, that works in your rifle fine. If you can't get that bullet, then the Berger 6.5mm, 140 grain, HYBRID TARGET bullet (SKU: 679459264143) should work just as well.
The "problem" is for the Reload Swiss (RS) powders, I don't see the Sierra or Berger bullets listed in their reloading data. They do show loads for the 6.5mm Hornady 140 grain ELD-M (which is their MATCH bullet), which is also an excellent choice if you can find them in Spain. The reloading data for the RS50, RS52, RS60, RS62, and RS70 powder and the 140 gr Hornady ELD-M bullets is shown below:
It sounds like you already reload for pistol calibers (9mm and .45) Do you have a chronograph? That will help you stay safe as you develop loads in your rifle. If you see your velocity shoot past the high end shown above for the particular powder you are using, you shouldn't go any further. If you notice stiff bolt opening, that's another warning sign to back off. No need to 'hot-rod' the gun! Stay within the velocity parameters shown in the chart, with the powder indicated, and you should be fine. You are more interested in a CONSISTENT load that is ACCURATE in your gun.