6.5mm Rapier Wildcat

Most factory calibres on offer to stalkers today will equally get the job done in the right hands when ensuring correct bullet placement and bullet construction. But sometimes it’s just nice to own something different. I quite fancied creating as an efficient cartridge design that I could, whilst using a quality existing parent case that would be in a deer calibre but could also double as a fox / long range round.

Roe

Introduction

Most factory calibres on offer to stalkers today will equally get the job done in the right hands when ensuring correct bullet placement and bullet construction. But sometimes it’s just nice to own something different. I quite fancied creating as an efficient cartridge design that I could, whilst using a quality existing parent case that would be in a deer calibre but could also double as a fox/long range round. Also it was to burn no more than 40-44 grains of powder and provide good velocity from a short 18 inch barrel initially.

18 inches allows a muzzle can to be fitted without increasing the overall length of the rifle, thereby making a highly practical stalking arm or 4x4 fox lamping kit. Calibre choice was settled on as 6.5mm due to my liking for the .260 Rem cartridge and regard for the venerable old 6.5x55. 

I had to find a parent case allowing maximum internal powder charge that would burn efficiently and totally within a short barrel but still provide safe pressures and good ballistics. Lapua 6.5x284 brass fitted the bill due to the rebated case design would be perfect when I reformed to a more squat format with highly efficient internal combustion chamber. The difficulty was in the case forming that would need a series of forming dies and final loading and bump dies.

I quickly drew up a reamer print and then sent to it Dave Kiff from Pacific Tool and Gauge in the States to have a barrel chamber reamer made with the correct throat for a 120 grain bullet and ordered a Walther Match grade stainless steel barrel with a varmint custom profile with total length of 18 inches unchambered and 1 in 8 twist rate. It would threaded to fit the switch barrel RPA Quadlite rifle that I use for calibre testing. It proved so efficient I had another barrel chambered the same but with a 28 inch length. 

Rationale behind the Rapier

The parent case, the 6.5x284 is 2.160inches long with a 35degree shoulder that burns 49 grains of powder to push a 129 or 130 grain bullet weight at 2850fps and 2327ft/lbs energy from a 24 inch barrel. A mighty fine cartridge in its own right but known for shorter than average barrel life but I wanted to achieve more realistic powder consumption yet still achieve longevity to the barrel and still turn out a cartridge that would send a 120 grain 6.5mm bullet out of that short barrel at 2800fps and develop 2090ft/lbs energy. The case would be only 1.88 inches long but have a more parallel profile and still keep the steep shoulder angles to decrease case stretching yet form a very short boxy internal chamber so that the powder charge could burn cleanly and highly efficiently to achieve maximum ballistic potential.

How is this possible I hear you ask if I intend to shorten the case by 0.28 inches, for the reason stated before , well certain calibres have a finite powder charge that works best within that calibre range, whereas the 6.5x284 is a little “overbored” the Rapier is just about right, well that was the theory.

Case forming

A series of four forming dies are used to gradually reduce the shoulder and neck junction back to its final position whilst reforming the shoulder angle and leaving a long neck for trimming.

The Rapier design utilises a case with a long neck of 0.337 inch not only for bullet support but also to ensure proper powder burning within the case for as long as possible. After Die 3 the case is trimmed to a length of 1.88 inches, the case is then deburred inside and out and then the neck is expanded with a mandrel starting with a 6mm and then a 6.5mm size. The reason being that in the forming process the neck is thickened a lot, and a small donut forms at the base on the neck internally, the 6mm mandrel smoothes out the neck and the 6.5mm size allows a neck turning mandrel to seat nicely.

Neck turning is essential to remove excess neck brass, in this cartridge one side is 24 thou thickness so at least half that needs to be removed to give a good neck tension that I wanted. Because the chamber dimensions of the reamer is 0.2904 I needed to turn the necks to allow a clearance for bullet release of at least 2 thou i.e. a thou a side minimum. I therefore neck turned to 0.287 inch and then when a 120 grain Sierra ProHunter bullet was seated in the case the o/d of the neck was 0.288 inch giving me the minimum requirements.

Die 4 is cut with the finishing reamer and is used as a true up die and a modified 6.5x284 body die ensures it chambers.

Wilson die blanks were re-chambered so that each reload was as consistent and accurate as possible with separate neck bushes. 

Field tests

Bullet weights between 85 to 140 grains give a reasonably wide choice for speedy flat shooting fox rounds and superb efficient high ballistic coefficient deer/long range loads.

Due to the relatively small boxy nature of the “burn” chamber and a water charge weight of 50 grains (bullet not seated) meant powders in the medium burn rate would yield the best results.

18 inch Barrel results. 

The light Sierra 85 grain bullets have a nice hollow point and I achieved 3167 fps and 1893 ft/lbs with a load of 43 grains of Vit N133 but because of the lack of bearing surface to seat they were a way off the rifling and accuracy was 1.0 inch.

Best lightest bullet was not the Berger 100 grain but the Lapua Scenar 108 gr bullet with a load of 42 grains H4895 achieving 3014 fps and a healthy 2017 ft/lbs. Not the top velocity but best accuracy at 0.45 inches for three shots.

Although the 120gr A-Max was outstanding, there is a 123 grain A-Max but I had none to test. A cracking load of 41.5 grains of Vit N540 spat out that high BC bullet at 2860 fps for 2180 ft/lbs and would genuinely group three shots into less than 0.35 inches at 100 yards.

Substituting the A Max for a Sierra Pro Hunter of 120 grains and 41grs of Vit N540 was a marriage made in heaven, 2866fps and 2189 ft/lbs and 0.5 inch groups. Better still for a deer load was the Hornady SST 129 grain bullet was well balanced at 40 grains of Vit N150 with a good velocity of 2850 fps and sublime accuracy of 0.25-0.35 inch.

140 grain bullets were fine but better in the longer barrel.

28 inch Barrel results

This is for your long range Varminting or just clanging steel silhouettes.

Again the 120 grain A-Max was superb, now a load of 45 grains of RL17 propelled that wind slippery bullet out at 3200 fps dead for 2728 ft/lbs. Accuracy too was very good 0.25-0.45 at 100 yards and still ½ MOA out to 600 yards.

The Lapua 123 gr Scenar too again with RL 17 powder, the Rapier likes this powder, shot 3111 fps/2642 ft/lbs with 44 grains and if anything was more accurate than the A –Max.

Upping the weight to the Lapua 139gr Scenar and shifting to RL 19 powder and 46.75 grains gave solid 0.5 inch groups and 3013 fps.

The Berger 130 grain Match VLD was a surprise it was very accurate at 0.25-0.45 inches at 100 yards and seated way off the lands with 42 grains of Vit N150 powder fro 2929 fps and 2477 ft/lbs.

The Berger 140 grain VLD bullets also were very accurate and the RL17 came up trumps with 2955 fps and 2714 ft/lbs from a meagre 42.5 grains load. 

18 inch Barrel (ballistics analysis quickload from JMS ARMS)

Bullet	Weight	Powder	Velocity fps	Energy ft/lbs
Sierra HP	85 gr	42gr Vit N133	3105fps	1819 ft/lbs
	85gr	43gr Vit N133	3167 fps	1893 ft/lbs
Berger Match BT	100gr	43gr RL15	2985 fps	1979 ft/lbs
	100gr	44gr RL15	3054 fps	2071 ft/lbs
Lapua Scenar	108gr	41gr H4895	2944 fps	1927 ft/lbs
	108gr	42 gr H4895	3014 fps	2017 ft/lbs
	108gr	42.5gr H4895	3048 fps	2063 ft/lbs
Hornady A -Max	120gr	40gr Vit N540	2790 fps	2075 ft/lbs
	120gr	41gr Vit N540	2831 fps	2136 ft/lbs
	120gr	41.5gr Vit N540	2860 fps	2180 ft/lbs
Sierra Pro Hunter	120gr	40gr Vit N540	2824 fps	2126 ft/lbs
	120gr	41gr Vit N540	2866 fps	2189 ft/lbs
Lapua Scenar	123gr	40gr Vit N540	2877 fps	2261 ft/lbs
	123gr	41 gr Vit N540	2914 fps	2320 ft/lbs
Hornady SST	129gr	40gr Vit N150	2850 fps	2327 ft/lbs
	129gr	41.5gr Vit N150	2913 fps	2431 ft/lbs
Hornady Interlock	140gr	44gr RL19	2665fps	2208 ft/lbs
	140gr	42gr       H 4350	2445 fps	1859 ft/lbs

28 inch Barrel (ballistics analysis quickloadfrom JMS ARMS)

Bullet	Weight	Powder	Velocity fps	Energy ft/lbs
Hornady A -Max	120gr	41gr Vit N140	3027 fps	2441 ft/lbs
	120gr	44gr RL17	3138 fps	2624 ft/lbs
	120gr	45gr RL17	3200 fps	2728 ft/lbs
Lapua Scenar	123gr	42.5gr RL17	3119 fps	2489 ft/lbs
	123gr	44gr RL17	3111 fps	2642 ft/lbs
Lapua Scenar	139gr	44gr RL19	2842 fps	2493 ft/lbs
	139gr	45 gr RL19	2904 fps	2603 ft/lbs
	139gr	46.75gr RL19	3013 fps	2801 ft/lbs
Berger Match VLD	130gr	40 gr Vit N150	2817 fps	2290 ft/lbs
	130gr	42gr Vit N150	2929 fps	2477 ft/lbs
Berger Match VLD	140gr	41.5gr RL17	2898 fps	2610 ft/lbs
	140gr	42.5  RL17	2955 fps	2714 ft/lbs

Conclusion 

The nearest comparisons are the .260 Remington round or the new 6.5x47 Lapua round or 6.5mm Creedmoor. 

As the Rapier shows it gives them all a run for their money 

With the lighter bullets the Rapier is a very serious longer range fox or varmint round that achieves great ballistics with minimal powder charge and retained down range performance. Here the 120 grain A –Maxes would be my choice. 

The 40 grains Vit N150 with SST`s was a good deer bullet with total lethality and minimal carcass damage whilst achieving good penetration and bullet expansion. 

Long range use would be spoilt for choice but the Berger 140 grain VLD`s shot tiny groups at all targets down range. 

I was pleased with the results but from a practical point of view I know this is not for every one and a .260 or 6.5x47 Lapua would certainly suffice or even the new 6.5 Creedmoor (shorten .260 case) from Hornady. 

Case prep is a serious pain in truth but as am 18 inch it’s a great woodland or hill deer gun and with the longer tube a static long range crow sniper, magic. 

The kit ( Reamer, Head Space (go and no go gauge)

 Kit (die blanks)

 Complete dies for chamber

 Cases during each stage of forming

Variety of bullet heads

The results

 Label here

Reloading kit

 Reloading kit

 Targets and tool dimension sheet

 Rifle and target results from tests

 Rifle and target results from tests

A scenic shot in Scotland

Steel Crow target plate

Steel Target plate

Munjac

Hunting results - 2 healthy foxes fall to the Rapier!

Hunting results - 2 healthy foxes

Bruce Potts

Contacts

Julian  07771 962121  Quickload Ballistics
Email : jmsarmsuk@gmail.com
      

Article and images by Bruce Potts