JDinFbg
Member
The long-standing belief is that 30-30 ammo intended to be shot in a tubular magazine rifle needs to have the bullets crimped to prevent the pressure from the magazine spring and the recoil of the rifle from causing the bullets to be pushed back into the case. I'm wondering if anyone has ever tested this belief? If so, how frequently do bullets, if not crimped, get pushed back into the case? Are we talking every round, 1 in 10, 1 in 100, 1 in 1000? How significant is the problem we're trying to solve by crimping the bullets? Here's why I ask.
I have been testing new loads for my Model 94 Winchester using Hornady's 160 gr. FTX bullet. I mistakenly first bought the 160 gr. bullet designed for the 308 Marlin Express (mfg. #30396). I single-shot loaded these in my rifle when testing group size with different powder loads, and it wasn't until I tried to feed these from the magazine that I realized they were too long to feed. However, they shot wonderfully in my Model 94 when single-shot loaded with the best load giving me a 4-shot group at 100 yds. measuring 0.722". The largest group I got was 2.839". When I obtained and tested the correct Hornady 160 gr. FTX bullet intended for the 30-30 (mfg. #30395), the results were downright dismal. I didn't get any groups smaller than 4.465".
This lead me to put together some dummy rounds using some junk cases and using 4 different bullets. The attached picture shows the 4 dummy rounds I made, all with the bullet seated to where the ogive just contacts the lands in my rifle barrel. The details are as follows:
1 - Hornady 160 gr. FTX 30-30 (mfg. #30395), O.A.L. = 2.602"
2 - Hornady 160 gr. FTX Marlin Express (mfg. #30396), O.A.L. = 2.707"
3 - Unknown brand 150 gr. round point, O.A.L. = 2.632"
4 - Sierra 170 gr. flat point, O.A.L. = 2.533"
SAAMI indicates the maximum cartridge length should be 2.550", but by tests I have found I can feed a cartridge as long as 2.617" in my Model 94 Winchester. The Hornady 30-30 bullet and the Sierra 170 gr. bullet are the only ones that would feed in my rifle loaded out to near where the bullet touches the lands, but the cannelure on the Hornady 30-30 bullet would be nowhere in the proper position for crimping.
Based on seating the bullet to the top of the cannelure, I measured the approximate amount of bullet jump I would get as follows
1 - 0.068" jump
2 - 0.007" jump
3 - 0.075" jump
4 - 0.010" jump
The large bullet jump for the Hornady 160 gr. FTX 30-30 bullet probably explains the dismal results I got with that bullet, and the small jump with the Hornady 160 gr. FTX Marlin Express bullet likely explains why I got some fairly small groups with it. I haven't tested the 150 gr. round nose or the Sierra 170 gr. flat nose, but I would expect that the 170 gr. bullet with its small jump would perform the best.
If I didn't have to seat to the cannelure so I could crimp the bullets for my 30-30, I would have much more flexibility in optimizing the bullet jump and a better chance of producing ammo that shoots well in my rifle. Thus my interest in knowing whether anyone has ever tested un-crimped ammo in
their tubular magazine 30-30 rifles. I'm also wondering if not expanding the case necks before seating the bullet would produce a great enough hold on the bullet to avoid the need for crimping?
I have been testing new loads for my Model 94 Winchester using Hornady's 160 gr. FTX bullet. I mistakenly first bought the 160 gr. bullet designed for the 308 Marlin Express (mfg. #30396). I single-shot loaded these in my rifle when testing group size with different powder loads, and it wasn't until I tried to feed these from the magazine that I realized they were too long to feed. However, they shot wonderfully in my Model 94 when single-shot loaded with the best load giving me a 4-shot group at 100 yds. measuring 0.722". The largest group I got was 2.839". When I obtained and tested the correct Hornady 160 gr. FTX bullet intended for the 30-30 (mfg. #30395), the results were downright dismal. I didn't get any groups smaller than 4.465".
This lead me to put together some dummy rounds using some junk cases and using 4 different bullets. The attached picture shows the 4 dummy rounds I made, all with the bullet seated to where the ogive just contacts the lands in my rifle barrel. The details are as follows:
1 - Hornady 160 gr. FTX 30-30 (mfg. #30395), O.A.L. = 2.602"
2 - Hornady 160 gr. FTX Marlin Express (mfg. #30396), O.A.L. = 2.707"
3 - Unknown brand 150 gr. round point, O.A.L. = 2.632"
4 - Sierra 170 gr. flat point, O.A.L. = 2.533"
SAAMI indicates the maximum cartridge length should be 2.550", but by tests I have found I can feed a cartridge as long as 2.617" in my Model 94 Winchester. The Hornady 30-30 bullet and the Sierra 170 gr. bullet are the only ones that would feed in my rifle loaded out to near where the bullet touches the lands, but the cannelure on the Hornady 30-30 bullet would be nowhere in the proper position for crimping.
Based on seating the bullet to the top of the cannelure, I measured the approximate amount of bullet jump I would get as follows
1 - 0.068" jump
2 - 0.007" jump
3 - 0.075" jump
4 - 0.010" jump
The large bullet jump for the Hornady 160 gr. FTX 30-30 bullet probably explains the dismal results I got with that bullet, and the small jump with the Hornady 160 gr. FTX Marlin Express bullet likely explains why I got some fairly small groups with it. I haven't tested the 150 gr. round nose or the Sierra 170 gr. flat nose, but I would expect that the 170 gr. bullet with its small jump would perform the best.
If I didn't have to seat to the cannelure so I could crimp the bullets for my 30-30, I would have much more flexibility in optimizing the bullet jump and a better chance of producing ammo that shoots well in my rifle. Thus my interest in knowing whether anyone has ever tested un-crimped ammo in
their tubular magazine 30-30 rifles. I'm also wondering if not expanding the case necks before seating the bullet would produce a great enough hold on the bullet to avoid the need for crimping?