TargetTalk

Hi,

I just went out with a new chrono and tested some N310. (Please disregard the data on the 4.0gr load because the rounds were older using a budget bullet and I can't verify the weight of the powder to be 4.0 for sure.)

Does the data look within expectations for 3.8 gr of N310 pushing a 200 gr LSWC by Missouri Bullet Company (18bhn) with an OAL 0f 1.255? I believe MBC uses a H&G 68 clone mold.

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I use N310 for my long line load: New starline brass, Zero 185gr JHP, 4.3gr of N310, 1.200" OAL and 0.468" crimp. It shoots 1.4" at 50 yards (5 shots) out of my Les Baer wad gun with the 1.5" group option.

I ransomed many guns all with kart NM barrels and 3.9 v-n310 always shot average of 2-2.5'' @50 yrds with 185 lswc-hps, better with 185 fmj-hp noslers and 4.5gr. no need to go hotter with 200 same charge was very accurate with it too.

Did you record the temperature on the days that you tested? N310 is a temperature sensitive powder, and a difference in ambient temp of even 10-15 degrees can change your velocity quite a bit.

Very interesting to know that. All were shot the same day, Monday this week and the temps were in the upper 70's.

I use N310 on both 200 LSCW and 185 Zero JHP. I don't go by speed, just group size. Using a Mountain Competition Pistol w/Schuemann AET Barrel.

185 Zero JHP = 4.5gr N310 =- 1.5" group at 50yds .470cr 1.205 oal
200 LSWC = 3.7gr N310 = 2.0" group at 50yds .470cr 1.244 oal

Enjoy testing!

Steve

Watch your OAL very carefully. And use only one kind of bullet for testing powders. The problem with using different bullets is that if the base is longer the powder chamber will be smaller, and the pressures will be higher. Any defects in the base of the bullet will often cause fliers.

Since cheap bullets are likely to vary more in weight, you will also see a bigger spread on the velocities.

Thanks folks. I discovered the difference after I deconstructed a bullet with the low fps.

I agree accuracy is the main goal and I will be testing loads with a rest but I was very curious about velocity and variance. I am questioning if a 834 FPS round will have the same result as an 770 FPS round all else being equal.

I made new rounds with 4.0 gr N310 pushing 200 gr Missouri Bullets (the same bullets I used for the 3.8 gr 4.0 load. I used a single headstamp.

I haven't re- measured yet but there is a chance the 3.8 gr rounds pushing the 200 gr's have a slightly shorter OAL which may account for the higher velocity. I may be looking at 1.250 vs 1.255 OAL. Comparison with re-made 4.0 gr loads:

[img][img]http://i78.photobucket.com/albums/j113/ ... istics.png[/img][/img]

. . . .

I shot the n-310 loads for a long time and it was always accurate as far as temp sensitive many powders are to some extent, I never saw much change except once when the temp was in the 40's the rounds seemed a little lighter but were still accurate.

New Test results for N310 3.7 gr. I tried to correlate accuracy with ballistics. OAL 1.255. Opinions? I was a bit disappointed with three shots that were out of the 1.5" group.

[img][img]http://i78.photobucket.com/albums/j113/ ... -20-14.png[/img][/img]

Been using for over 10 years. VV310 has been very, very good to me.

However with the bullseye level charge weights, I will tell you that ballistic consistency and accuracy for me seems to hinge on: (1) WW Large Pistol Primer to ensure good consistent ignition of the small charges (it is rated for standard and mag loads and I don't see the temperature sensitivity that some other people mention), (2) a very consistent combustion chamber size (read consistent bullet seating depth using a shoulder seating die) and (3) a good crimp (for example 0.469 to 0.470 with Oregon Trail lead SWC and Federal brass).

Yes, you will get higher velocity with heavier bullet since the combustion chamber is smaller with the same seating depth. I shoot the 200 gr SWC at 50 and just drop in the 185 gr. bullets for the shot line loads.

VV 310 seem to have a pretty wide "sweet spot" for charge weights and if you find the middle ground for your load combination, a couple of tenths either way doesn't seem to blow the grouping or sight setting.

By the way, you might want to try 3.85 gr. and the Oregon Trail bullets. :-0

Just my simple observations. Hope this might prove helpful.

Cecil

Thanks CR.

I used Winchester LP. My crimp is .471-.472, should I tighten it up a bit? As I read posts on this thread - everyone is using a tighter crimp. I'm using a 1.255 OAL and I think most use shorter. My goal was to be close to the rifling.

My press is a Dillon and I am very curious about the shoulder bullet seating, anyone have any suggestions?

Were the 185's you speak of cast or jacketed? If cast what charge were you using?

chiltech500 wrote:Thanks CR.

I used Winchester LP. My crimp is .471-.472, should I tighten it up a bit? As I read posts on this thread - everyone is using a tighter crimp. I'm using a 1.255 OAL and I think most use shorter. My goal was to be close to the rifling.

My press is a Dillon and I am very curious about the shoulder bullet seating, anyone have any suggestions?

Were the 185's you speak of cast or jacketed? If cast what charge were you using?

I would not go any longer than a factory OAL. Some pistols have relatively short chambers. I borrowed ammo once at a match, from a guy who had a longer OAL. The bullets would not function in my gun.

If you are getting perfect functioning with your crimp, leave it alone. Just make sure your press is locked down so it doesn't get any looser.
If you think it is causing issues tighten down to .369.


I use the shoulder seating die made by Steve Bathje. It does keep me from having to readjust the press as long as I stick with semi wadcutters. It also tends to yield a more consistent shoulder height as long as you don't get so much wax buildup in the die that it pushes the entire bullet down too far.

Being closer to the rifling doesn't help. Having a properly sized bullet for your barrel is what engages the rifling.

My average OAL with Oregon Train 200 or 180 gr is 1.238 to 1.240.

Seating is with the seater that Isabel mentioned or you can just take a 3/8 inch drill and do it yourself if you are handy and have the equipment.

Both the 200 and 185 mentioned are Oregon Trail. Slightly expensive for lead, always available, extremely consistent and very accurate for me from Kart barrels.

If you go to jacketed 185's JHP (Nosler) I generally need to get up to 4.2 grains or better for best accuracy and function with most guns.

Please note to all I said "for me", "I generally" and "most".

To each his own and good shooting.

Cecil

Having a properly sized bullet for your barrel is what engages the rifling

I would assume the plunk test for OAL and width would do that trick, no?

I use the shoulder seating die made by Steve Bathje

How do I find this, or maybe I could buy another die insert for my Dillon and drill out as CR10x mentions.

"Having a properly sized bullet for your barrel is what engages the rifling."

This means that the lead bullet should be just tiny amount larger than the barrel groove diameter. Much smaller or larger and you can get of leading and not so good accuracy. We're talking in the 1/1000ths here. Just mic various cast bullets and you'll see. They most all say .452 +/-, but that +/- can make a difference. Pick the one that your barrel likes the best.

I have found that barrels are somewhat like trying to get a date. Generally they will like you or not and there's not much to can do to improve the initial situation; but there are lots of things you can do to make it worse.

CR

So what I'm hearing you say is I should buy some different mfg's bullets and accuracy test them and see which works out best.

Here is the gauge I use for measuring "plunk test" results. I have various length dummy bullets made (1.260, 1.255, 1,250, 1.245 etc) at a couple different widths. I drop them in the barrel and look to see how they line up. FYI factory RN ammo is quite low almost lower than the 2nd image from the left. Mine are the 3rd image.

[img][img]http://i78.photobucket.com/albums/j113/ ... ting-3.jpg[/img][/img]

What you are showing is for overall cartridge length, etc.

For lead bullets we are taking about the actual diameter of the bullet relative to the bore of the barrel.

These are two entirely differnt measurements. You have a lot of control over the length of the cartridge through bullet seating.

The diameter is what you buy and you ain't changing that. Each bullet caster may have slightly different alloys, moulds, etc that will result in one company's nominal .452 diameter and alloy being great for your barrel and another nominal .452 diameter and alloy bullet being just so-so.

Cecil

I must be missing something. When I crimp the round the only unchanged portion is the shoulder - does that mean the slight variation between one mfgs' .452 and another matter?

Would measuring the inside diameter of my barrel and a bullet tell me if they are compatible?